TEST BANK & SOLUTIONS MANUAL for Human Physiology: An Integrated Approach 8th Edition by Silverthorn Dee Unglaub.
Exam Name
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Physiology is the study of
A) the normal function of living organisms.
B) the tissues and organs of the body at the microscopic level.
C) growth and reproduction.
D) the structure of the body.
E) the facial features as an indication of personality.
2) The literal meaning of the term physiology is knowledge of A) organs. B) math. C) science. D) chemistry. E) nature. 2)
3) Because anatomy and physiology have different definitions, they are usually considered separately in studies of the body.
A) True B) False
4) The following is a list of several levels of organization that make up the human body.
1. tissue
2. cell
3. organ
4. molecule
5. organism
6. organ system
The correct order from the smallest to the largest is
A) 4, 2, 3, 1, 6, 5.
B) 4, 2, 1, 3, 6, 5.
C) 6, 4, 5, 2, 3, 1.
D) 2, 4, 1, 3, 6, 5.
E) 4, 2, 1, 6, 3, 5.
5) "Glucose is transported from blood into cells because cells require glucose to meet their energy needs." This type of explanation is
A) teleological.
B) scatological.
C) mechanistic.
D) theological.
E) metalogical.
6) "Glucose is transported from blood into cells by transporters in response to insulin." This type of explanation is
A) scatological.
B) mechanistic.
C) metalogical.
D) theological.
E) tele olo gic al.
7) Which is a buffer zone between the outside world and most of the cells of the body?
A) red blood cells
B) extracellular fluid
C) cell membrane
D) intracellular fluid
E) All of the answers are correct.
8) Which is one of Cannon's "internal secretions"?
A) nutrients
B) hormones
C) water
D) inorganic ions
E) None of the answers are correct.
9) The study of body function in a disease state is
A) histology.
B) necrology.
C) microbiology.
D) pathophysiology.
E) physiology.
10) Homeostasis is the ability of the body to
A) prevent excessive blood loss.
B) ignore external stimuli to remain in a state of rest.
C) quickly restore changed conditions to normal.
D) prevent the external environment from changing.
E) prevent the internal environment from changing.
11) Oxytocin is a hormone released in response to cervical dilation. This causes more uterine contractions that will further dilate the cervix. Which type of feedback does oxytocin trigger?
A) positive feedback
C) local control
B) negative feedback
D) nociceptive feedback
12) How genetics influences the body's response to drugs is called
A) pharmacodynamics.
B) pharmacokinetics.
C) pharmageddon.
D) pharmacogenomics.
E) paleopharmacology.
13) A physician basing clinical decisions on primary research published in biomedical literature is doing medicine.
A) evidence-based
B) traditional
C) whimsical
D) alternative
E) holistic
14) A study in which a participant act as an experimental subject in part of the experiment and a control in another part of the experiment is called a study.
A) crossover B) meta-analysis C) double-blind D) retrospective
15) The Internet database for molecular, cellular, and physiological information is called the Project.
A) Physiome
B) Manhattan
C) Physiosome
D) Human Genome
E) Physiognomy
16) A placebo is
A) a nutritive and respiratory organ in fetal development.
B) any drug being tested in a clinical trial.
C) any drug in a class of drugs commonly used as pain relievers.
D) a hole in a cavity wall through which an organ protrudes.
E) a drug or treatment that is expected to have no pharmacological effect.
17) A technique used to resolve contradictory results in scientific studies is
A) longitudinal analysis.
B) prospective analysis.
C) retrospective analysis.
D) cross-sectional analysis.
E) meta-analysis.
18) A scientifically logical guess is a
A) theory.
B) hypothesis.
C) law.
D) variable.
E) model.
19) If a scientific model is supported or verified repeatedly by multiple investigators, it may become a
A) law.
B) variable.
C) model.
D) theory.
E) hypothesis.
20) Place these terms in the typical sequence in the process of scientific inquiry: experimental data, theory, model, observation, hypothesis, replication.
A) observation, replication, model, experimental data, hypothesis, theory
B) experimental data, theory, model, observation, hypothesis, replication
C) replication, hypothesis, experimental data, theory, model, observation
D) theory, observation, experimental data, hypothesis, replication, model
E) observation, hypothesis, experimental data, replication, model, theory
21) You are interested in learning more about Parkinson's disease, a neurological disorder that mainly affects motor function. Which is the best source to begin your investigation?
A) physiology textbook
B) public library
C) Ask.com
D) a physician
E) MedlinePlus
22) Which system(s) does NOT exchange material with the internal and external environments?
A) urinary system
B) respiratory system
C) circulatory system
D) digestive system
E) All of the above.
23) The human environment is terrestrial, dry, and highly variable. However, our bodies expend enormous amounts of energy maintaining a constant internal environment. Studying why our bodies do this is what kind of approach?
A) teleological
B) mechanistic
C) translational
D) meterological
E) anatomical
24) Individuals with Type I diabetes mellitus do not make enough insulin. Which would be a mechanistic explanation of how insulin is used by the body?
A) Insulin binds to its receptor which stimulates the movement of glucose transporters to the cell membrane.
B) Since all cells need glucose, insulin is required.
C) Insulin is a hormone involved in glucose transport.
D) Without insulin most cells in the body would be unable to produce enough ATP.
E) Cells need insulin because glucose will not cross the cell membrane.
25) Excretion is a function of the body. Which would be considered excretion?
A) Movement of salt from sweat glands to the surface of the skin.
B) Movement of potassium from kidney cells into one's urine
C) Movement of glucose from the kidney to the bloodstream.
D) Movement of sodium from the intestines to the bloodstream.
E) Movement of oxygen from the lungs to the blood stream.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
26) What is a nocebo effect?
27) List the key concepts or themes in physiology.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
28) Adaptive significance is an important concept in physiology because it describes the
A) parameters necessary to maintain a constant internal environment.
B) importance of a highly variable external environment.
C) similarities between ancient and modern marine organisms.
D) ability of an organism to monitor and restore its internal state to normal conditions when necessary.
E) physiological functions that promote an organism's survival.
29) You conduct an experiment on twenty 18-year-old male subjects to see how various intensities of exercise affect heart rate. Which is/are an independent variable?
A) age of subjects
B) sex of subjects
C) heart rate
D) intensity of exercise
E) More than one answer is correct.
30) You conduct an experiment on twenty 18-year-old male subjects to see how various intensities of exercise influence heart rate. Which is/are a dependent variable?
A) heart rate
B) intensity of exercise
C) sex of subjects
D) age of subjects
E) More than one of the answers is correct.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
31) Why are physiology and anatomy frequently studied together?
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
32) You want to display data on the finish times of the 10 fastest race horses in a single race at the Kentucky Derby. Which type of graph would be best to display this information?
A) line graph
B) bar graph
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
C) scatter plot
33) You want to display data on the finish times of the 10 fastest race horses in a single race at the Kentucky Derby. What would the labels be for the graph axes?
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
34) A horse runs 10 races, each a mile long, during a 6-month period, and you are interested in determining if the horse's race finish time changes with experience. Which type of graph would be best to display this information?
A) scatter plot
B) bar graph
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
C) line graph
35) A horse runs 10 races, each a mile long, during a 6-month period, and you are interested in determining if the horse's race finish time changes with experience. What would the labels be for the graph axes?
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
36) There are 10 cloned horses, born on the same day, with identical chromosomes. They each follow the same physical training regimen, but are given daily injections of different concentrations of a particular vitamin. They all run the same race. Which type of graph would be best to explore a relationship between race finish time and vitamin dose?
A) scatter plot
B) bar graph
C) line graph 36)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
37) There are 10 cloned horses, born on the same day, with identical chromosomes. They each follow the same physical training regimen, but are given daily injections of different concentrations of a particular vitamin. They all run the same race. What are the labels for the graph axes?
38) What is the difference between a peer-reviewed article and a review article?
39) What is an example of the deconstructionist view of biology?
40) Sahra has just flown around the world in the last 48 hours. She is having trouble sleeping, a condition known as insomnia. How do you think Sahra's long flights and her insomnia are related to biological rhythms?
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
41) Why do we need to label the axes of a graph? 41)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
42) You go outside on a very cold day and you start to shiver because you do not have on the proper clothing. The act of shivering would represent what step in a response loop?
A) response
B) integrating center
C) variable
D) sensor
E) setpoint
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
43) Explain why the prefix homeo- is used in the term homeostasis Why do some physiologists prefer the term homeodynamics over homeostasis?
44) Explain why animals are used in research. Are there any limitations to the application of animal data to human physiology? Could these limitations be addressed using cell or tissue culture, or computer simulations?
45) You conduct an experiment on twenty 18-year-old male subjects to see how various levels of exercise influence heart rate. Explain why only 18-year-old males were used as subjects.
46) Use these terms to develop a reflex loop: brain, sensory neuron, an eye, foot, soccer ball, motor neuron
47) Provide an example of a control system. Be sure to include the three main parts: an input signal, an integrating center, and an output signal.
48) Write a teleological explanation for why heart rate increases during exercise. Now write a mechanistic explanation for the same phenomenon.
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
49) What is a hypothesis? What are the steps involved in following the scientific method? How does one distinguish the dependent variable from the independent variable in an experiment? How are each of these represented on a graph?
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
50) You are designing a study to assess the effects of a new treatment for hypertension. What ethical considerations would you employ when monitoring your progress?
51) You are designing a study to assess the effects of a new drug treatment for hypertension. Your subjects are white males, ages 40 to 60 years. Can your study results be applied to all people? Explain.
52) High cholesterol levels have been shown to be a contribute to heart disease and death for many decades. In the 1970s, scientists used this information to develop a hypothesis that giving a medicine to reduce blood cholesterol levels could reduce the chances of developing cardiovascular disease or dying from cardiovascular disease. They tested a group of people living in Framingham, Massachusetts. This study became known as the Framingham Study, and it is very well known because it did not support the hypothesis. Does this mean that high cholesterol is not a risk factor for heart disease? What does this demonstrate about the scientific process, especially as it relates to human studies? You can find a copy of the study online and read it, if necessary.
Use the table and graph below to answer the following questions.
53) List all of the errors in Figure 1.1.
54) Why is a line graph to used to show the results of this study?
55) Use Table 1.1 to graph the data appropriately. What can you CONCLUDE based on the new figure?
Use the table and graph below to answer the following questions.
56) Summarize the data shown in Figure 1.2.
57) Referring to Table 1.2, what general trend in systolic blood pressures is seen as both males and females increase in age?
58) Referring to Figure 1.2, at approximately what ages do males have higher systolic blood pressures than females? At what age does this trend reverse?
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
59) The human body is best described as always being in a state of equilibrium such that all body compartments are identical.
A) True B) False 59)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
Following is a table of data collected from one section of an 8 A.M. physiology lab. There were 20 students present, 10 males and 10 females. Information collected included students' height, weight, age, sex, and resting pulse rate. In addition, the students were surveyed to see if they smoked cigarettes, considered themselves "regular exercisers," and if they had consumed caffeine or eaten the morning of the lab. A "y" or "n" (yes or no) was recorded to indicate their answers. Each student did "jumping jacks" for 5 minutes and recorded the time required to return to their resting heart rate, which is lis the table as "recovery time." Finally, each student's reaction time (in milliseconds) was measured by catching an object droppe partner according to specified criteria. Use this table to answer the following questions. Ignore statistical problems caused by small sample size, and so on.
For these questions, the data were separated and analyzed by gender.
60) Refer to Table 1.3 and Figure 1.3
A. Write a hypothesis regarding gender and weight.
B. What is the dependent variable? What is the independent variable?
C. Based on the data in the graph above, what is your conclusion?
D. Why is a bar graph a good choice for presentation of these data? Would another type of chart be as effective?
61) Refer to Table 1.3.
A. Write a hypothesis regarding sex and recovery time.
B. What is the dependent variable? What is the independent variable?
C. Create a graph using the averages from the data table. Based on these data, what do you conclude?
62) Refer to Table 1.3.
A. Write a hypothesis regarding the effects of breakfast consumption on reaction time.
B. What is the dependent variable? What is the independent variable?
63) Refer to Table 1.3.
A. Ignoring the sex of the subjects, write a hypothesis that expresses the relationship between weight and height.
B. What is the dependent variable? What is the independent variable?
C. Construct a graph that examines relationship between weight and height.
64) Table 1.3 shows data on various factors that may or may not be related to resting pulse rate, time to recovery to resting pulse rate after a few minutes of exercise, and reaction time measured by how quickly a student could press a keyboard key after seeing a computer-generated prompt. For each question below, write a testable hypothesis, identify the dependent and independent variables, sketch an appropriate graph of the results, and dr conclusion from the data presented in the table. Discuss your results.
A. Does caffeine consumption have an effect on resting pulse rate?
B. Does age play a role in resting pulse rate? Does weight?
C. Is there a relationship between eating breakfast and recovery time?
D. Is there a relationship between reaction time and height?
E. Do females who smoke show differences in their resting pulse rates compared to female nonsmokers or to ma smokers and male nonsmokers?
F. Does regular exercise have an effect on resting pulse rate?
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
65) The law of mass balance states
A) if one is to survive they must have a certain amount of mass.
B) that all matter is neither created or destroyed.
C) if a substance is to remain constant any gain must be offset by an equal loss.
D) that homeostasis can be maintained when the load of a substance is continuously lost.
E) that all substances in the body have equal mass.
66) Mass balance involves determining the total amount of a substance in the body. We can determine mass flow of this substance by which formula?
A) (concentration of a substance) × (volume/min)
B) (concentration of a substance) / volume flow
C) (amount of substance / min) × (concentration of the substance)
D) intake + production - excretion - metabolism.
E) volume of flow / (amount of substance / min) 66)
67) are kept within normal range by physiological control mechanisms which are used if the variable strays too far from its
A) Independent variables, steady state
B) Setpoints, regulated variable
C) Steady state values, integrating center
D) Dependent variables, lowest value
E) Regulated variables, setpoint
68) Vasodilation of blood vessels supplying muscles in response to increased carbon dioxide during exercise is an example of
A) long-distance control.
B) neural control.
C) reflex control.
D) hormonal control.
E) local control.
69) Which are used to keep our systems at or near their setpoints?
A) open control loops
B) response loops
C) negative feedback loops
D) positive feedback loops
E) feedforward control loop
Answer Key
Testname: UNTITLED20
1) A
2) E
3) B
4) B
5) A
6) B
7) B
8) B
9) D
10) C
11) A
12) D
13) A
14) A
15) A
16) E
17) E
18) B
19) D
20) E
21) E
22) C
23) A
24) A
25) A
26) It is the phenomenon whereby a patient who has been informed of the side effects of a drug he or she is taking is more likely to experience some of the side effects than an otherwise similar patient receiving the same drug who has not been so informed.
27) See Table 1.1 in the chapter.
28) E
29) D
30) A
31) This is discussed in the "Physiology Is an Integrative Science" section of the chapter.
32) B
33) The x-axis is horse name or number; the y-axis is finish time in minutes.
34) C
35) The x-axis is race number or date; the y-axis is finish time in minutes.
36) A
37) The x-axis is vitamin dose; the y-axis is finish time in minutes.
38) A peer-reviewed article describes original research by one author (or group of authors working together) that has gone through a screening process in which a panel of qualified scientists evaluate the work. A review article is a summary (usually a collection of published research that was previously peer-reviewed, usually from more than one independent lab) that discusses a particular topic in the field.
39) The deconstructionist view of biology predicted that once we uncovered the sequence of the human genome, the inner workings of the human body would be revealed. In reality, it is possible to know HOW a gene codes for a particular protein without knowing WHY that protein exists. Our knowledge of the human genome is only a piece of the puzzle.
40) Our sleep-wake cycle is a biological rhythm that lets our body know when it is time to rest. Most likely Sahra has ignored the signals like sleepiness, changes in body temperature, and mood that her body is sending. By ignoring these rhythms, she has disrupted the cycle and the body is struggling to maintain homeostasis.
41) A graph with no axis labels is meaningless–without knowing what trend is being illustrated, there is no communication of scientific information.
42) A
43) The prefix homeo, meaning like or similar, is used to indicate that the body's internal environment is maintained within a range of acceptable values rather than a fixed state. Some physiologists argue that the term homeodynamics better reflects the small but constant changes that continuously take place in the internal environment, as opposed to homeostasis, which erroneously implies lack of change.
44) (Note to instructor: This may be a good question to ask early in the semester, then again toward the end, after the organ systems have been covered.) There is a brief discussion of using humans or animals in research in the chapter. This question is intended to stimulate students to think about how science is done, how data are generated, and how the process is challenged by social issues. Generally, there are limitations to the usefulness of computer simulations and cell/tissue culture systems for the same reason that nonhuman animal data are not 100% applicable to human physiology. How human organ systems perform may be different in very subtle ways from corresponding systems in other species. Cells in culture are in an artificial environment, and while much has been learned from such systems, it has also been noted that the behavior of cells in culture is not identical to cells in a living body. Furthermore, cells cultured from established lines can change over time, becoming less like the original cells from which they were derived, and presumably less like normal cells. Computer simulations are valuable, but are only as good as the data entered, and given that we don't know everything there is to know about physiology, we can't write a perfect computer program. All three approaches are useful, but for different reasons, and therefore one research system does not completely substitute for another, nor is it appropriate to abandon one entirely.
45) An important part of scientific inquiry is to remove sources of variation from among subjects. By choosing subjects of one gender in a particular age group, it is easier to determine that the dependent variable (heart rate, in this case) depends ONLY on the independent variable, level of exercise. This also allows a study to have fewer participants, assuming that subjects were randomly assigned to a level of exercise. If subjects were of random ages and genders, data would have to be collected from many more individuals.
46) Eye sees soccer ball.
Sensory neuron sends visual information.
Brain receives information and formulates a plan.
Motor neuron sends action information from the brain.
Foot and leg muscles contract, and the ball is kicked.
47) Variable. One example is blood glucose concentration. The input signal is a blood glucose concentration outside of the normal range, the controller is the pancreas, and the output signal is release of either insulin or glucagon.
48) Teleological: Heart rate increases because the increased activity of skeletal and cardiac muscles requires increased delivery of blood contents such as oxygen and glucose. Mechanistic: Heart rate increases in response to signals from the brain (pacemaker cells of the heart are stimulated by the nervous system).
49) This is discussed in "The Science of Physiology" section of the chapter and in Figure 1.15.
50) Major considerations should involve assessing the efficacy of the treatment such that the control group patients are not deprived as well as ensuring that the experimental treatment is not less effective than the standard treatments.
51) Possibly, but not necessarily. There are gender differences in appropriate therapies because of physiological effects of higher testosterone in males compared to females, for example. Drugs are often not tested in children, and children also have a different hormonal environment than adults (again, sex hormones are a good example, because their levels are low until just before the onset of puberty). There are also racial differences in effectiveness of therapies, and while it is a contentious issue as to whether these represent genetic or socioeconomic influences, they should be considered.
52) This demonstrates the difficulty in doing human research because, even though elevated cholesterol levels are a risk factor for cardiovascular disease, reducing cholesterol levels without addressing the reason those levels were high in the first place may not have the expected effect on reducing heart disease. Human testing on hypotheses is important because humans don't always respond to treatments like other animals do, they may actually respond quite differently and each person may respond differently from the rest. It is why we need to test each hypothesis in circumstances as similar to the actual real group that would be treated.
53) 1. The units of concentration are labeled as M when they should be mg.
2. The x-axis is in decreasing order of concentration.
3. The graph needs a legend.
54) Line graphs are commonly used when the independent variable (x-axis) is a continuous phenomenon. In this study the concentration of epinephrine is a continuous function. The line allows for interpolation (i.e., estimating values between the measured values).
55) Graphs should address the errors in Figure 1.1.
This small sample suggests that an increase in epinephrine concentration increases the average heart rate of Sprague-Da rats.
56) The systolic pressure of both genders increases with age. Under age 40, the systolic pressure of males is higher than that of females. After age 40, the systolic pressure of females is higher than that of males. The greatest rate of increase is from ages 50 to 70 in both genders. Blood pressure declines after age 70.
57) The systolic pressure of both genders increases until age 70 but declines after age 70.
58) From age 10 to 40, male pressures are higher; after age 40, female pressures are higher.
59) B
60) A. Males weigh more than females.
B. Weight depends on gender; thus weight is dependent, gender is independent.
C. Males weigh more than females.
D. Bar graph allows comparison of the average of two groups. No.
61) A. A prediction such as "Males recover from exercise more quickly than females" would be appropriate.
B. The independent variable is sex; the dependent variable is recovery time.
C. A bar graph such as the one below is appropriate. In this study, males recovered from exercise more quickly than fem
62) A. A prediction such as "Eating breakfast prior to testing improves reaction time of subjects (compared to subjects who eat breakfast)" is appropriate.
B. The independent variable is breakfast consumption; the dependent variable is reaction time.
Answer Key
63) A. A prediction such as "As height increases, weight increases" would be appropriate. B. The dependent variable would be weight; the independent variable is height. C.
64) Answers will vary, but examples follow (conclusions written here are based on cursory examination of graphed data–n statistical tests of significance were performed).
A. Hypothesis: Caffeine consumption increases heart rate.
Independent variable: caffeine consumption.
Dependent variable: resting pulse rate.
Conclusion: Mean pulse rates between caffeine-drinking (68 bpm) and control subjects (73 bpm) are similar (large varia between individuals); hypothesis not supported.
B. Hypothesis: Pulse rate is lower in older subjects and is higher in heavier subjects.
Independent variables: age and weight.
Dependent variables: resting pulse rate.
Conclusion: Pulse rate was similar in all groups; hypothesis not supported.
C. Hypothesis: Subjects who ate breakfast have a faster reaction time.
Independent variable: breakfast consumption.
Dependent variable: pulse rate.
Conclusion: Subjects who ate breakfast had a faster reaction time (168.7 msec vs. 180.5 msec); hypothesis supported.
D. Hypothesis: There is no relationship between height and reaction time.
Independent variable: height.
Dependent variable: reaction time.
Conclusion: Reaction time did not vary with height; hypothesis supported.
E. Hypothesis: Smokers of both sexes have a higher resting pulse rate than nonsmokers of either sex, and males and fem affected equally.
Independent variables: smoking and sex.
Dependent variable: pulse rate.
Conclusion: There was no difference in pulse rate in any of the groups (70.4 bpm in nonsmokers vs. 70.3 bpm in smoker hypothesis not supported.
F. Hypothesis: Subjects who exercise regularly have a lower resting pulse rate.
Independent variable: exercise.
Dependent variable: pulse rate.
Conclusion: Regular exercise had no effect on resting pulse rate (68.9 bpm in nonexercisers vs. 71.8 bpm in exercisers); hypothesis not supported.
Discussion may cover issues such as the effect of small sample size, use of adults of limited age range, lack of control ov treatments (Were the subjects honest about age, eating breakfast, consuming caffeine, smoking, and exercising? Were the quantitative data of height and weight determined in the lab using the same equipment and same data collector?), the value of statistical analysis, and so on. It is likely that students will be surprised by some of the results and could make erroneous conclusions. For example, pulse rate may vary with age, but without including children and senior citizens in the sample population, this trend would be missed.
65) C
66) A
67) E
68) E
69) C
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Stanley Miller set out to demonstrate an explanation for the origins of organic molecules using a combination of simple organic molecules, heat and periodic bursts of electricity through the mixture, ultimately producing which kind of molecules?
A) glycoproteins
B) amino acids
C) nucleic acids
D) lipids
E) carbohydrates
2) Glycosylated molecules are formed with
A) lysosomes.
B) cholesterol.
C) nucleic acids.
D) carbohydrates.
E) DNA.
3) Cells regulate their level of activity by regulating the amount of proteins in the cell at any given time, so an up-regulation of enzymes would be expected to
A) increase the cell's response produced by the reaction catalyzed by the enzyme.
B) have no effect on the rate of reactions catalyzed by the enzyme.
C) decrease the level of productivity of chemical reactions that rely on the enzyme.
D) decrease the rate of reactions catalyzed by the enzyme.
E) decrease the level of productivity of chemical reactions that rely on the enzyme and decrease the rate of reactions catalyzed by the enzyme.
4) When an enzyme reaches its saturation point, the amount of
A) substrate for the enzyme to act upon is very low and the amount of product produced by the enzyme decreases.
B) product produced continues to increase.
C) substrate for the enzyme to act upon is high.
D) substrate for the enzyme to act upon is low.
E) product produced by the enzyme decreases.
5) Which element make up more than 90% of the body's mass?
A) C, Na, K B) O, Ca, H C) O, H, Na D) Ca, C, O E) O, C, H
6) Phospholipids are key components of cell membranes and made up of which molecules?
A) nucleotides
B) amino acids
C) fatty acids
D) glycerol and fatty acids
E) glycerol
7) Chromium is
A) a dietary supplement with no natural role in the body.
B) an essential element involved in glucose metabolism.
C) a protein.
D) not an element in the periodic table.
8) Which is a way to recognize a carbohydrate by looking at its name?
A) It begins with proteo.
B) It begins with lipo-
C) It ends in -ase.
D) It begins with nucleo-
E) It ends in -ose.
9) Which is NOT an essential element for a living organism?
A) nitrogen B) mercury C) oxygen D) carbon E) hydrogen
10) The largest carbohydrate molecules are called polysaccharides because they are made up of molecules bonded together with one another.
A) amino acid
B) nucleotide
C) pyrimidine
D) purine
E) simple sugar
11) Essential amino acids that are used to build proteins
A) exist in twenty six different forms.
B) can only be made by cells within our bodies.
C) must be derived from the foods we eat and digest.
D) are linked together by ionic chemical bonds in proteins.
E) can be used medically for both diagnosis and treatment of diseases.
12) Which is an example of a cation?
A) HCO3- B) Ca2+ C) Cl- D) SO42- E) HPO4212)
13) A positively-charged ion is called a(n)
A) proton. B) cation. C) electron. D) neutron. E) anion.
14) The most important polar molecule is because it is a universal solvent in biological solutions.
A) magnesium sulfate
B) water
C) nucleic acid
D) sodium chloride
E) bicarbonate
15) A substance is highly soluble if it is
A) very likely to dissolve in water and is called aqueous.
B) very likely to dissolve in water.
C) not very likely to dissolve in water.
D) not very likely to dissolve in water and is called aqueous.
E) called aqueous.
16) A free radical is a
A) molecule with an extra proton.
B) molecule with an extra neutron.
C) molecule with an extra electron.
D) charged particle.
E) molecule with an unpaired electron.
17) The chemical bonding behavior of an atom is directly determined by the
A) number and arrangement of electrons.
B) number of protons.
C) number of neutrons.
D) mass of the atom.
E) size of the atom.
18) Atoms in a covalent molecule share electrons
A) in single pairs.
B) in double pairs.
C) singly, never in pairs.
D) in triple pairs.
E) can share electrons in single pairs, double pairs, or triple pairs.
19) The weak interactions between atoms that keep atoms near each other are called
A) van der Waals forces and ionic bonds.
B) ionic bonds.
C) hydrogen bonds.
D) van der Waals forces.
E) hydrogen bonds and van der Waals forces. 19)
20) Which statement about carbohydrates is FALSE?
A) Simple sugars include galactose, glucose, and ribose.
B) Glycogen is a storage polysaccharide made by animal cells.
C) Polysaccharides include cellulose and glycogen.
D) Polysaccharides are important both for energy storage and to provide structure to cells.
E) Glycogen is important both for energy storage and to provide structure for cells. 20)
21) In lipids, unsaturated refers to
A) the ring structure of steroids.
B) fats, such as butter and lard, which come from animal sources.
C) the presence of double bonds between adjacent carbon atoms in a fatty acid.
D) glycerol, which acts as an anchor for joined fatty acids.
E) the absence of double bonds between adjacent carbon atoms in a fatty acid.
22) Each amino acid differs from others in the
A) chemical structure of the R group.
B) number of carboxyl groups.
C) size of the amino group.
D) number of central carbon atoms.
E) number of peptide bonds in the molecule.
23) The alpha-helix and B-sheets are examples of the structure of a protein.
A) primary
B) secondary
C) tertiary
D) quaternary
E) pentanary
24) Interactions between different globular or fibrous polypeptide chains result in which type of structure?
A) primary
B) secondary
C) tertiary
D) quaternary
E) pentagonal
25) The concentration of a solution expresses the amount of
A) solute per volume of solvent.
B) solvent per volume of solution.
C) solute per volume of solution.
D) solvent per volume of solute.
E) None of the answers are correct.
26) Nucleic acids are polymers of units called
A) amino acids.
B) bases.
C) ribose.
D) fatty acids.
E) nucleotides.
27) A nucleotide is made up of a
A) five-carbon sugar and an amino acid.
B) five-carbon sugar and phosphate group.
C) five-carbon sugar and a nitrogenous base.
D) phosphate group and a nitrogenous base.
E) five-carbon sugar, a nitrogenous base, and a phosphate group.
28) A nucleotide containing the base cytosine would base pairs with a nucleotide containing the base
A) cytosine. B) uracil. C) thymine. D) guanine. E) adenine.
29) An energy-transferring compound in cells is a nucleotide known as
A) glucose.
B) deoxyribonucleic acid.
C) fructose.
D) adenosine triphosphate.
E) protein.
30) Which bases are purines?
1. adenine
2. cytosine
3. guanine
4. thymine
5. uracil
A) 1 and 2 B) 1, 3, and 5 C) 2 and 3 D) 1 and 3 E) 2, 4, and 5
31) Biomolecule polymers are a typical formation of molecules.
A) inorganic
B) organic
C) either organic or inorganic
32) Cholesterol is a
A) component of animal cell membranes.
B) precursor to steroid hormones.
C) dangerous fat that is absent from a healthy body.
D) A and B
E) A, B, and C
33) An important buffer in the human body is A) NaCl. B) H+ . C) HCl.
34) Which of the following is most alkaline?
A) tomato juice, pH = 4
B) urine, pH = 6
C) lemon juice, pH = 2
D) stomach secretions, pH = 1
E) white wine, pH = 3
35) If a solution has a pH that is less than 7, it is A) a salt. B) a buffer. C) alkaline. D) acidic. E) neutral. 35)
36) Protein specificity is the
A) degree to which a protein-ligand complex initiates a response.
B) activation of a specific protein that is needed to perform a particular function.
C) degree to which a protein is attracted to a ligand.
D) ability of a protein to bind a certain ligand or a group of related ligands.
E) B and C 36)
37) Which is a common feature of soluble proteins?
A) chemical modulation
B) receptor binding
C) structural support
D) noncovalent interaction
E) All of the answers are correct.
38) An ion has gained or lost
A) proton(s).
B) neutron(s).
C) electron(s).
D) carbon atom(s).
E) double bond(s).
39) An isotope has gained or lose
A) proton(s).
B) neutron(s).
C) electron(s).
D) carbon atom(s).
E) double bond(s).
40) The number of determines the element.
A) protons
B) neutrons
C) electrons
D) carbon atoms
E) double bonds
41) This subatomic particle has a positive charge.
A) electron
B) sodium chloride
C) proton
D) neutron
E) molecular oxygen
42) This subatomic particle has a negative charge.
A) hydrogen
B) electron
C) magnesium
D) proton
E) neutron
43) This subatomic particle has a neutral charge.
A) electron
B) proton
C) neutron
D) magnesium
E) hydrogen
44) A change in pH value of one unit indicates a
A) 1-fold change in [H+].
B) change of 10-2 in pH.
C) 10 fold change in [H+].
D) change of 10-1 in pH.
E) Cannot be determined.
45) A blood pH of less than 7.00 and greater than 7.70 is incompatible with life.
A) True B) False
46) Which statement describes the relationship between pH and hydrogen ions?
A) pH and hydrogen ions are inversely related.
B) pH and hydrogen ions are independent and unrelated.
C) pH and hydrogen ions are equivalent.
D) pH is always 100 times more than the number of hydrogen ions.
E) pH and hydrogen ions are directly related. 46)
47) HCl (hydrochloric acid) is an acid because
A) in solution it donates its H+ .
B) in solution it increases the pH.
C) it is able to form hydroxide ions.
D) in solution it decreases the concentration of free H+
E) it is similar to ammonia.
48) Molecular structure and function of large complex biomolecules result from which interactions?
A) ionic bonds
B) hydrogen bonds
C) van der Waals forces
D) covalent bond angles
E) All of the choices can contribute. 48)
49) Which formula describes the relationship between pH and hydrogen ions?
A) pH = log [H+]
B) pH= [H+] + [OH-]
C) [H+] = -log pH
D) pH = -log [H+]
E) [H+] = log pH
50) All organic molecules contain
A) adenosine. B) lipids. C) carbon. D) oxygen. E) calcium. 50)
51) Molecules that contain carbon are known as
A) atoms.
B) nonessential elements.
C) minerals.
D) protons.
E) organic molecules. 51)
52) Which elements make up 90% of the body's mass?
A) carbon dioxide, oxygen, and sodium
B) oxygen, carbon, and nucleic acids
C) sodium, potassium, and calcium
D) hydrogen, nitrogen, and oxygen
E) oxygen, carbon, and hydrogen
53) Which results when an atom has such a strong attraction for electrons that it pulls one or more electrons completely away from another atom?
A) ionic bond
B) Van der Waals attraction
C) covalent bond
D) weak bond
E) hydrogen bond
54) These are weak attractive forces that are responsible for the surface tension of water.
A) Van der Waals attractions
B) covalent bonds
C) ionic bonds
D) hydrogen bonds
E) potassium bonds
55) These result when the carbon atoms in phospholipids share a pair of electrons.
A) potassium bonds
B) ionic bonds
C) covalent bonds
D) Van der Waals attractions
E) hydrogen bonds
56) Van der Waals forces are weak attractive forces between the nucleus of one atom and the electrons of another atom close by.
A) True
57) Glycogen is an example of a
A) nucleotide.
B) carbohydrate.
C) lipid and protein.
D) protein.
E) lipid.
58) Nucleotides perform which function(s)?
B) False
A) They are the building blocks of proteins like cell receptors.
B) They transfer energy and are part of genetic material.
C) They store glucose as fat.
D) They are the starting material for steroid hormones.
E) They form structural elements in the cell membrane. 58)
59) Which biological molecules exhibit saturation, specificity and competition?
A) lipids
B) proteins
C) lipids and proteins
D) nucleotides
E) carbohydrates
60) Triglycerides and steroids are examples of
A) carbohydrates.
B) proteins.
C) nucleotides.
D) lipids.
E) lipids and proteins.
61) Potassium channels are usually made up of several subunits. This is an example of which level of protein structure?
A) primary
B) secondary
C) tertiary
D) quaternary
E) alpha helix
62) The sequence of amino acids in the chain is an example of which level of protein structure?
A) primary
B) secondary
C) tertiary
D) quaternary
E) alpha helix
63) Hemoglobin molecules are made from four globular protein subunits. The three-dimensional shape of these globular subunits is an example of which level of protein structure?
A) primary
B) secondary
C) tertiary
D) quaternary
E) alpha helix
64) β-strands are an example of a flat arrow arrangement of amino acids.
A) True
B) False
65) Which level of protein structure occurs from spontaneous folding that results from covalent bonds and noncovalent interactions?
A) triangular
B) tertiary
C) primary
D) quaternary
E) secondary 65)
66) The protein keratin which is found in hair and nails is categorized as which protein shape?
A) globular
B) acidic
C) triangular
D) fibrous
E) hexavalent
67) Which types of bonds between amino acids plays an important role in the shape of globular proteins?
A) collagen bonds
B) disulfide bonds
C) metallic bonds
D) sodium bonds
E) secondary bonds
68) Which would be disrupted by changes in free hydrogen ions in solution, thus disrupting the molecule's shape and function?
A) double bonds
B) sodium bonds
C) hydrogen bonds
D) covalent bonds
E) disulfide bonds
69) During intense exercise our muscles produce lactate and hydrogen ions. Which molecules would be affected by the accumulation of hydrogen ions?
A) DNA in the nucleus
B) phospholipids in the membrane
C) glucose molecules in the adipose tissue
D) the proteins actin and myosin
E) cholesterol in the plasma membrane
70) Which best describes an irreversible antagonist?
A) binds to proteins away from the active site
B) reversible agonist
C) involved in activation via phosphorylation
D) allosteric enhancer
E) cannot be displaced by competition
71) Protein kinase A is a molecule inside our cells that can activate enzymes within the cell. Protein kinase A does this by adding phosphates to the enzymes. This is which type of modulation?
A) competitive inhibitor
B) allosteric modulator
C) reversible antagonist
D) covalent modulator
E) irreversible agonist
72) A reaction is stopped by substance X but can recover when more of the customary ligand is supplied. Substance X is an example of a
A) competitive inhibitor.
B) phosphatase.
C) covalent modulator.
D) irreversible antagonist.
E) allosteric modulator.
73) Which is an allosteric modulator?
A) A substance that binds irreversibly.
B) A substance involved in activation via phosphorylation.
C) A substance that can be displaced by competition at the active site.
D) A substance that has no effect on the affinity of the ligand.
E) A substance that binds to proteins away from the active site.
74) The smallest organizational level is a(n) A) tissue. B) element. C) molecule. D) nucleus. E) atom.
75) When two or more atoms are chemically linked, they form a(n) A) nucleus. B) molecule. C) atom. D) tissue. E) element.
76) Oxygen, carbon, and hydrogen, along with eight other elements are considered A) compounds.
B) molecules.
C) major essential elements.
D) minor essential elements.
E) atoms.
77) The center of an atom is called the A) molecule. B) electron. C) element. D) nucleus. E) proton.
78) Electrons travel around the center of the atom at high speed forming a(n) A) nucleus. B) shell. C) atom. D) element. E) molecule.
79) An element's ability to bind other elements is determined by
A) the arrangement of electrons in the outer shell of an atom.
B) the amount of folding in its subunits.
C) its state of glycosylation.
D) its amino acid composition.
E) the number of enzymes required.
80) Ions with a positive charge are called A) electrons. B) cations. C) tissues. D) anions. E) neurons.
74)
75)
77)
78)
79)
80)
81) Ions with a negative charge are called A) anions. B) electrons. C) neurons. D) tissues. E) cations. 81)
82) A is a made up of solutes dissolved in a solvent.
A) nucleus
B) molecule
C) cocktail
D) compound
E) solution
83) Substances that easily dissolve in water are
A) lipids.
B) isotonic.
C) nonpolar.
D) hydrophobic.
E) hydrophilic.
84) Substances that do not dissolve well in water are
A) hydrophilic.
B) isotonic.
C) polar.
D) hydrophobic.
E) salts.
85) A(n) is any molecule or ion that binds to a receptor protein.
A) ligand
B) vitamin
C) enzyme
D) cofactor
E) phospholipid
86) Two methods of protein activation include and
A) homeostatic, osmotic
B) proteolytic, cofactor binding
C) mechanistic, covalent bonding
D) exergonic, endogonic
E) enzymatic, glycolytic
87) DNA contains the five-carbon sugar
A) lactose.
B) deoxyribose.
C) uracil.
D) glucose.
E) ribose. 87)
88) RNA contains the five-carbon sugar
A) glucose.
B) uracil.
C) deoxyribose.
D) ribose.
E) lactose. 88)
89) The purines found in DNA are and .
A) cytosine, thymine
B) cytosine, uracil
C) deoxyribose, guanine
D) guanine, cytosine
E) adenine, guanine
90) The pyrimidines found in DNA are and
A) guanine, cytosine
B) deoxyribose, guanine
C) adenine, guanine
D) cytosine, uracil
E) cytosine, thymine
91) In a chemical reaction, between atoms are broken as atoms are rearranged in new combinations to form different chemical substances.
A) chemical bonds
B) electron shells
C) homeostatic interactions
D) protons
E) nuclei
92) The reaction rate of many chemical reactions that occur in the body are controlled by molecules called
A) nucleic acids.
B) enzymes.
C) purines.
D) neurotransmitters.
E) intermediates.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
93) How many milliequivalents are represented by a mole of bicarbonate ions (HCO3-)?
94) List and define the seven categories of soluble proteins.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
95) Which elements combine to form nonpolar covalent bonds?
A) carbon and hydrogen
B) carbon and chlorine
C) hydrogen and oxygen
D) sodium and chlorine
E) nitrogen and hydrogen
96) The symbol Ca2+ means calcium has
A) lost two protons.
B) gained two protons. C) lost two electrons.
D) gained two electrons.
97) In a 5% NaCl solution,
A) there are 5 grams of sodium chloride for every 100 mL of water.
B) the solute is water.
C) there are 5 grams of sodium chloride for every 100 mL of total solution.
D) A and B
E) A and C
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
98) A molecule of sucrose has a molecular weight of 342 Daltons. How many grams of sucrose would be required to make one liter of a 2.5 Molar solution of sucrose?
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
99) A covalent double bond is formed when atoms
A) swap two pairs of electrons.
B) transfer a pair of electrons from one atom to the other.
C) transfer two pairs of electrons from one atom to the other.
D) share one pair of electrons (a total of two).
E) share two pairs of electrons (a total of four).
100) The term polar is used to describe molecules because
A) there are at least two distinct ends of the molecule regarding electron position and the resulting charge.
B) polar covalent molecules were first discovered in polar bears.
C) such molecules are always linear in shape.
D) there are at least two distinct ends of the molecule regarding hydrogen placement.
E) polar covalent molecules are found in colder climates.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
101) The more likely a fat is to be solid at room temperature, the more it potentially can contribute to cardiovascular disease. With this in mind, which fats will be the most dangerous?
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
102) Lipids are hydrophobic, and do not usually dissolve in water. Because blood is water-based, the lipid cholesterol is combined with so it can be transported by blood.
A) cations
B) hydrophilic molecules
C) anions
D) nothing; cholesterol is not transported in blood
E) hydrophobic molecules
103) Only free H+ contributes to the hydrogen ion concentration.
A) True B) False
104) In the equation CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3, which of these is an acid? A) CO2 B) HCO3- C) H2CO3 D) H2O
E) H+
103)
105) Chemical reactions that occur in the human body proceed at a faster rate due to special catalytic molecules called
A) enzymes.
B) cytozymes.
C) proteins.
D) antagonists.
E) antibodies.
106) The fuel molecule cells use to run all their activities is A) vitamins. B) glucose. C) sucrose. D) starch. E) protein.
107) A fatty acid that contains three double bonds in its carbon chain is said to be
A) carboxylated.
B) saturated.
C) monounsaturated.
D) hydrogenated.
E) polyunsaturated.
108) Most of the lipid found in the human body is in the form of A) monoglycerides.
B) phospholipids.
C) steroids.
D) prostaglandins.
E) triglycerides.
109) Each of the following is a function of proteins EXCEPT
A) signaling.
B) catalyst.
C) transport.
D) storage of genetic information.
E) binding to ligands.
110) If a polypeptide contains 10 peptide bonds, how many amino acids does it contain? A) 11 B) 10 C) 0 D) 5 E) 12
111) Glycoprotein molecules
A) allow atoms to pack closely together and occupy minimum space.
B) increase the solubility of lipids.
C) act as buffers in body fluids.
D) aid in the formation of chemical bonds between carbon atoms.
E) create a coat on the cell surface that assists in cell aggregation and adhesion.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
112) Compare and contrast the role of up-regulation and down-regulation of proteins.
113) What is the induced-fit model? List the types of bonds involved and classify them as strong or weak.
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
114) The of a solution is the negative logarithm of the hydrogen ion concentration, expressed in moles per liter of solution.
115) When a nitrogenous base is bonded to a pentose sugar and a phosphate, a is formed.
116) Solutions are formed with water and solutes which dissolve in them. 116)
117) The molecules which form the bilayer region of the cell membrane have hydrophilic regions on the outer surface and hydrophobic regions on the inner surface.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
118) Compare and contrast the chemical bonds between adjacent monomers in DNA, and between two strands of DNA.
119) Compare and contrast the general chemical structures of monosaccharides and amino acids.
120) What are functional groups? List the common functional groups in biological molecules.
121) True or False? Lipids are hydrophobic because they easily dissolve in water. If true what allows them to dissolve in water or if false, what is it about their molecular structure that makes them less likely to dissolve in water?
122) Explain the polar character of an ammonia molecule (NH3). What is the cause of the partial charges? What is the overall charge for NH3?
123) Water striders are insects that literally walk on water. These insects are frequently found living on ponds. If hydrogen bonds did not exist, how would this affect the life of water striders?
124) If the dissociation constant of a protein is less than one (Kd < 1), what can you conclude about the affinity of the protein for the ligand?
125) Noncovalent molecular interactions occur between many different biomolecules and often involve proteins. Give an example of such an interaction and what the function might be.
126) Tenzin is assigned a project regarding ions, isotopes, and free radicals. Her teacher tells her that she has to describe what is similar between them, and how they are different. Tenzin is having some trouble, and calls you in for help. Assuming she has learned and understood some basic chemistry, help her organize her thoughts by making a table or flow chart.
127) Ahmed is trying to memorize chemical structures of every compound his professor has indicated are important to the human body. Explain to him that an easier way is to memorize a few rules of chemical bonding and then figure out the structure of the important compounds, especially the simpler compounds.
128) Define polar covalent, nonpolar covalent, ionic, and hydrogen bonding. Which of these bonds involves more than one molecule? Which of these bonds is/are important in determining the properties of water? Explain.
129) Ionic bonds are considered to be strong chemical bonds. Yet, ions dissociate in water. Explain how both can be true.
130) Your swimming buddy, Mario, jumped into a pool parallel to the water surface. When he stood up, he yelled "ouch," and you noticed that the skin on his chest and belly looked red and irritated. How would you describe the properties of water to explain to Mario why this happened? Why doesn't it hurt when pool water is penetrated perpendicular to the surface, as with a hands-first or feet-first dive?
131) You are helping your dad prepare food in the kitchen. Dad has a tablespoon of water in one hand and a tablespoon of vegetable oil in the other, when he trips over the rug and spills both spoons on the countertop. Dad notices that the oil forms a thin film on the countertop, whereas spilled water forms smaller, taller beads. How should you explain the different behavior of these liquids to your dad?
132) Mahamoud is confused on the similarities and differences between proteins and nucleic acids. Assuming he has learned and understood the basic chemistry, what is the likely source of his confusion? To help him sort this out, make a table or flow chart to explain the structure of these molecules and their relationship to each other.
133) Proteins are described as having different levels of structure. List and distinguish between the level(s) that produce a linear shape vs. a globular shape, and explain why one of those levels can result in either a linear or globular shape.
134) While every level of a protein's structure is important to the function of that protein, which level of structure is most important to the function of enzymes, and why?
135) You are a student intern in the research and development department of a pharmaceutical company. You have discovered a compound that destroys the common cold virus in cultured human cells. Chemical characterization reveals that carbon, hydrogen, and oxygen are present, in a 20:40:4 ratio of C:H:O. Experiments in rats show that neither oral nor injectable treatment with the compound was effective in destroying the virus. Discuss some possible reasons for this lack of effectiveness.
136) Describe what happens to NaCl when placed in water.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
137) How many grams of glucose, molecular mass = 180 Daltons, is necessary to make 1 liter of a 1.0 molar solution?
A) 180
B) 1.0
C) 90
D) 360
E) 6.02 × 1023
138) A 5 M solution of 100 mL of glucose contains how many grams of glucose, molecular mass = 180 Daltons?
A) 90
B) 6.02 × 1023
C) 180
D) 1.0
E) 360
139) If 100 mL of water contains 5 grams of NaCl, molecular mass = 58.5 Daltons, what is the molarity of the solution in moles/L?
0.085 B) 0.25
0.85
2.92
0.05
140) How many grams of NaCl, molecular mass = 58.5 Daltons, are the molar equivalent to 90 g of glucose (molecular mass = 180 daltons)?
0.5
14.6
117
0.25
29.25
141) How many grams of NaCl, molecular mass = 58.5 Daltons, are necessary to make 1 liter of 5% saline?
A) 58.5
B) 6.02 × 1023
C) 50
D) 1 E) 2.9
142) A typical blood concentration of glucose is 100 mg/dL. The molecular weight of glucose is approximately 180 Daltons. What is the molarity of this solution in millimoles?
100
0.56
5.6
10
18
143) If in an acid-base reaction H2SO42- donates two H+ , one mole of H2SO42- would equal how many equivalents?
2
1
0.75
0.5
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
144) What is the difference between atomic mass and molecular mass.
4
145) A. Distinguish between the mass of a molecule and the mass of a mole, using NaCl in your example.
B. Calculate the mass of a mole of NaCl in g, using the mass of one Da (amu).
C. Calculate the mass of a dozen NaCl molecules, a dozen donuts, and a mole of donuts, assuming a 30 gram do
146) Write the chemical formula for the molecule drawn below. Which class of organic molecule does it belong to? Is likely polar or nonpolar?
147) What is the pH of a 0.005 M HCl solution? Assume complete dissociation.
Answer Key
Testname: UNTITLED21
1) B
2) D
3) A
4) C
5) E
6) D
7) B
8) E
9) B
10) E
11) C
12) B
13) B
14) B 15) B
16) E
17) A
18) E
19) E
20) E
21) C
22) A
23) B
24) D
25) C
26) E
27) E
28) D
29) D
30) D
31) B
32) D
33) E
34) B
35) D
36) D
37) D
38) C
39) B
40) A
41) C
42) B
43) C
44) C
45) A
46) A
47) A
48) E
49) D
50) C
Answer Key
Testname: UNTITLED21
51) E
52) E
53) A
54) D
55) C
56) A
57) B
58) B
59) B
60) D
61) D
62) A
63) C
64) A
65) B
66) D
67) B
68) C
69) D
70) E
71) D
72) A
73) E
74) E
75) B
76) C
77) D
78) B
79) A
80) B
81) A
82) E
83) E
84) D
85) A
86) B
87) B
88) D
89) E
90) E
91) A
92) B
93) 1000 milliequivalents. This is calculated by taking the equivalent value of the molecule, which equals the molarity of the molecule (1 in this case) times the number of charges the molecule carries (in this case, the minus symbol indicates a charge of negative one, i.e., -1), so 1 × 1 = 1 equivalent. 1 equivalent = 1000 milliequivalents.
94) The seven categories: enzymes, membrane transporters, signal molecules, receptors, binding proteins, regulatory proteins, and immunoglobulins. See the "Protein Interactions" section of the chapter.
95) A
96) C
97) C
Answer Key
Testname: UNTITLED21
98) 805 grams (per liter). This is calculated by multiplying the amount of sucrose in one liter of a 1 molar solution (342 grams) times the molar concentration (2.5). 342 × 2.5 = 805 grams
99) E
100) A
101) The more saturated or the higher the number of hydrogens a fat contains, the more likely it will be solid at room temperature. Therefore, saturated animal fats are the most associated with cardiovascular disease.
102) B
103) A
104) C
105) A
106) B
107) E
108) E
109) D
110) A
111) E
112) These terms refer to the net change in the amount of a functional protein present in a cell in response to a signal. Up-regulation is an increase in the amount of the protein, whereas down-regulation is a decrease.
113) The interaction between a protein binding site and a ligand that are in close proximity results in a conformational change of the protein to fit more closely to the ligand. The bonds involved are hydrogen (weak), ionic (strong), and van der Waals (weak).
114) pH
115) nucleotide
116) hydrophilic
117) phospholipid
118) The bonds holding monomers together are covalent bonds, between sugar and phosphate molecules. The bonds holding neighboring strands together at the complementary bases are hydrogen bonds.
119) Monosaccharides consist of carbon, hydrogen, and oxygen, in the ratio C:H:O of 1:2:1. Amino acids consist of a central carbon (CH), a carboxylic acid (COOH), an amine (NH2), and an organic side chain of variable structure (mainly a hydrocarbon chain, designated as R).
120) Several combinations of atoms that occur repeatedly in biological molecules. See Table 2.1 in the main text.
121) False. Lipids are considered hydrophobic because they have an even distribution of electrons and no positive or negative poles. Thus, nonpolar molecules have no regions of partial charge, and therefore tend to repel water molecules.
122) When chemically bonded with each other, the nitrogen atom is partially negative whereas the hydrogen atoms are partially positive. The nitrogen atom in a molecule of ammonia has a stronger attraction for the electrons participating in the covalent bonds than the hydrogen atoms. The net charge on the molecule is still zero, however.
123) Hydrogen bonds are responsible for the surface tension of water, the attractive force between water molecules that can make it difficult to separate them. The surface tension is strong enough to support the weight of water striders, thus allowing them to walk on water. If water molecules could not form hydrogen bonds, the water striders would not be able to walk on water because there would be no surface tension to support their weight. Therefore, these insects would have to adapt to terrestrial conditions near ponds or lakes rather than living on them.
124) Since Kd < 1, you know that [P][L] < [PL]. Therefore, at equilibrium, there is a higher concentration of protein-ligand complex suggesting that the protein has a relatively high binding affinity for the ligand.
125) Examples of such interactions would be the interactions between carbohydrates, proteins, and lipids. These interactions form molecules like glycolipids and glycoproteins. These molecules are usually used as signaling molecules on the surfaces of cells.
126) All of these terms are similar in that they describe a structure that has either gained or lost something but different in their overall function. An ion is an atom that has gained or lost one or more electrons and thus bears an electrical charge Ions form when salts dissolve in water and are required for normal cell function. An ion's charge affects both its behavior in solution and its chemical reactivity. An isotope is an atom that has gained or lost one or more neutrons; as neutrons lack a charge, isotopes remain neutral. Some isotopes emit radiation, a type of energy, rendering them both useful and dangerous; compared to ions, they are rare in nature. A free radical is an atom or molecule that has at least one unpaired electron (an electron is more stable if paired with another electron). Free radicals can be either electrically charged (e.g., superoxide) or neutral (e.g., hydroxy), depending upon the total number of protons and electrons present. Because free radicals are unstable, they are highly reactive and disruptive to cell function; compared to ions, they are rare in the body. Neither isotopes nor free radicals are known to be required for normal cell function.
127) Elements combine to form molecules in predictable ways because of how the outer shell electrons combine between atoms. In most cases, the outer shell will be most stable with a total of eight electrons. This information is easily discernible from the periodic table. Therefore an atom with seven outer shell electrons, such as K, combines very readily with an atom with one outer shell electron, such as Cl; an atom with six outer shell electrons, such as Ca will combine with an atom with two outer shell electrons or with two atoms with one outer shell electron each, and so on.
Examples: KCl, CaCl2, CH4.
128) Polar covalent bonds occur within a single molecule that shares electrons unequally; i.e., the constantly orbiting electrons spend more time at some locations and less at others. Nonpolar covalent bonds occur within a single molecule that shares electrons equally; i.e., the probability of an electron occupying a particular location is the same at all locations. Ionic bonds occur within a single molecule in which one atom completely loses an electron to another, causing each to develop an opposite charge; it is this electrical attraction that holds the molecule together. Hydrogen bonding occurs between separate molecules that contain polar covalent bonds; where electrons spend more time the molecule is partially negative, and where electrons spend less time the molecule is partially positive. The ends of different molecules are thus electrically attracted to each other. Water is a polar covalent molecule, with the oxygen end being partially negative and attracted to the partially positive hydrogen portions of other water molecules. Hydrogen-bonding between water molecules is responsible for surface tension and the crystalline structure of ice.
129) Molecules such as sodium chloride are bonded by ionic bonds. So much energy would be required to separate a molecule of NaCl into Na+ and Cl- that it is practically impossible. That is, if the sodium chloride is DRY. Because water molecules have partial charges resulting from their polar covalent bonds, sodium chloride dissociates in water. This means that the ions separate and function relatively independently. An attraction between sodium and chloride still exists, however, and the dissociation can be described as an increase in bond length rather than a loss of the bond. Evaporate the water, though, and the sodium chloride crystals reform.
130) Because Mario was parallel to the water surface, the force of his mass was spread out over a relatively large area of the water, making the force per unit water lower than in a typical dive. The surface tension of water, while not strong enough to keep Mario from penetrating the water surface, was strong enough to momentarily resist him. The force of the water pushing back on Mario, however briefly, was enough to cause pain. In a typical dive position, the force of Mario's entire mass is spread only over a tiny area of the water, and thus the force per unit water surface is greater. This higher force is sufficient to immediately break the hydrogen bonds and overcome the surface tension.
131) Water forms beads when it strikes a nonabsorptive surface because of surface tension resulting from the hydrogen bonds between neighboring water molecules. Vegetable oil molecules are nonpolar covalent, therefore, there is no hydrogen bonding between the lipid molecules and no bead formation.
132) His confusion probably stems from the fact that both proteins and nucleic acids are classified as macromolecules, and both are assembled by covalently bonding certain monomers in a particular order. Also, nucleic acids contain the information necessary for manufacturing proteins, the term acid is used in describing the structure of both nucleic acids and proteins, and both nucleic acids and proteins must contain nitrogen. The monomer of protein is the amino acid, which has a central carbon, a variable chain denoted as R, and a nitrogen-containing amino group. There are 20 naturally occurring amino acids. The monomer of the nucleic acid is the nucleotide, which has a sugar attached to a nitrogen-containing base, and a phosphate. There are five different bases and two different sugars. The sequence of bases in a DNA or RNA molecule determines the sequence of amino acids in the protein.
133) Linear shapes: primary, secondary, quaternary. Primary structure is simply the sequence of covalently bonded amino acids in a peptide chain. Secondary structure is further bonding between nearby amino acids in a peptide chain, with the molecule still retaining a strand-like shape. Quaternary structure can involve separate linear polypeptide chains held together in a strand. Globular shapes: tertiary and quaternary. Tertiary structure involves bonding between distant amino acids, which causes the molecule to be wadded. Quaternary structure occurs when more than one globular peptide chain bonds together.
134) Enzymes and other globular proteins depend upon the three-dimensional shape resulting from the globular folding. Under conditions in which this shape is altered by denaturing agents such as heat, the protein ceases to function, though the primary and secondary structure may be unchanged.
135) The relatively low amount of oxygen and high carbon and hydrogen indicate that this compound is probably a lipid. Oral administration may result in digestion of the compound so that none is absorbed into the blood. Lipids are not highly soluble in water, and because blood is a watery medium, the injected lipid may not transport well in the blood. Also, human cells as well as the viruses may behave differently in culture compared to in a real patient.
136) Water molecules break the ionic bonds holding Na+ and Cl- together. Each sodium ion becomes surrounded by polar water molecules, with the electronegative ends of water molecules interacting with the ion. Each chloride ion also becomes surrounded by polar water molecules, but in this case it is the electropositive ends of the water molecules that bind to the ion. A consequence is that sodium and chloride ions can function relatively independently of each other when in solution.
137) A
138) A
139) C
140) E
141) C
142) C
143) A
144) The atomic mass is the actual mass of an atom, expressed in atomic mass units (amu) or Daltons (Da), where 1 amu = 1.6 × 10-27 kg. However, molecular mass is the sum of the atomic mass of each element × the number of atoms of each atom that make up the molecule.
145) A. The mass of a molecule is determined by the mass of its component atoms. From the periodic table, the mass of Na is 23 amu and of Cl is nearly 36 amu, so the mass of one molecule of NaCl is 59 Da. A mole is like a dozen, i.e., it is a particular number of items, specifically 6.02 × 1023
B. A mole of NaCl = 59 Da × 6.02 × 1023 = 3.55 × 1025 Da.
1 Da = 1.66 × 10-27 kg, so 3.55 × 1025 Da × 1.66 × 10-27 kg/Da × 1000 g/kg = 59 g.
C. A dozen NaCl molecules: 12 × 59 Da × 1.66 × 10-27 kg/Da × 1000 g/kg = 1.2 × 10-21 g.
A dozen donuts: 12 × 30 g = 360 g. A mole of donuts: 6.02 × 1023 × 30 g = 1.8 × 1025 g.
146) C11H12N2O2. The presence of the carboxylic acid (COOH) and amine (NH2) indicates this is an amino acid. Because of the R group structure, it is relatively nonpolar (this amino acid is tryptophan).
147) pH = 2.3. If pH = - log [H+] and HCl is a strong acid, we can assume complete dissociation will occur in solution.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) When cancer develops in one tissue and spreads to another through the blood or the lymph, the cancer is said to have undergone what process?
A) cytokinesis B) mutation C) metastasis D) differentiation
2) The space that is surrounded by the tissue wall of hollow organs is known as the
A) tract.
B) extracellular space.
C) lumen.
D) peritoneal cavity.
E) epidural space.
3) The lumen of a hollow organ such as the stomach is considered to be part of the environment.
A) external B) internal
4) The watery medium that surrounds a cell is known as
A) protoplasm.
B) cytoplasm.
C) intracellular fluid.
D) extracellular fluid.
E) cytosol.
5) Which term is NOT used to define the structure that separates the contents of a human cell from its surrounding medium?
A) plasma membrane
B) a cell wall
C) a cell membrane
D) plasmalemma
E) All of the answers are correct.
6) Which of the following is NOT a function of membrane proteins?
A) respond to extracellular molecules
B) act as transport molecules for various solutes
C) creating junctions between cells
D) anchor or stabilize the cell membrane
E) produce energy
7) Cell membranes are said to be
A) impermeable barrier.
B) selectively permeable barrier.
C) freely permeable barrier.
D) only permeable to water soluble molecules.
E) None of the answers are correct.
8) What is/are the major role(s) of the phospholipid bilayer in the cellular membrane?
A) the formation of a barrier that is selective for lipid-soluble molecules
B) the absorption of fats only
C) to carry water-soluble molecules through a hydrophobic environment
D) to provide a framework for membrane proteins only
E) the formation of a barrier that is a selective for lipid-soluble molecules and to provide a framework for membrane proteins
9) Which of the following is NOT a membrane lipid?
A) phospholipids
C) sphingolipids
B) cholesterol
D) All are membrane lipids.
10) Which structure is a lipid bilayer that controls which objects can leave or enter the cell?
A) Golgi apparatus
B) ribosome
C) plasma membrane
D) endoplasmic reticulum
E) nucleus
11) A liposome is a
A) a structural part of cell membranes.
B) medium to deliver drugs.
C) medium to deliver cosmetics.
D) a type of lipid.
E) a medium to deliver cosmetics and drugs.
12) An immunoliposome is a liposome that
A) can recognize cancer cells.
C) stimulates the immune system.
13) Intermediate filaments
A) stabilize the position of organelles.
B) transport materials within the cytoplasm.
C) provide the cell with strength.
D) form the neurofilaments in nerve cells.
E) All of the answers are correct.
B) suppresses the immune system.
D) None of the answers are correct. 12)
14) Which proteins assist in the movement of vesicles along microtubules?
A) kinesins
B) rough endoplasmic reticulum
C) Golgi complex
D) mitochondria
E) ribosomes
15) Which is an example of a membranous organelle?
A) cilia
B) centriole
C) ribosome
D) cytoskeleton
E) lysosome
16) The thickest protein fibers from the following group are
A) myosin molecules.
B) microfilaments.
C) neurofilaments.
D) microtubules.
E) keratin filaments.
17) Ribosomal RNA is formed by
A) lysosomes.
B) nucleoli.
C) the endoplasmic reticulum.
D) mitochondria.
E) Golgi complexes.
18) Which statement about mitochondria is FALSE?
A) The mitochondrial cristae form the inner membrane forming separate compartments.
B) The mitochondria produce most of a cell's ATP.
C) The intermembrane space plays an important role in mitochondrial ATP production.
D) The mitochondria do not contain DNA nor RNA.
E) The matrix of the mitochondria contains metabolic enzymes involved in energy production.
19) In humans, only cells have flagella.
A) intestine lining
B) respiratory tract lining
C) stomach lining
D) sperm
E) uterine tube lining
20) Tay-Sachs is a disease caused by having defective
A) smooth endoplasmic reticulum.
B) lysosomes.
C) mitochondria.
D) Golgi bodies.
E) rough endoplasmic reticulum.
21) Microvilli are found
A) in large numbers on cells that secrete hormones.
B) only on cells lining the reproductive tract.
C) in cells that participate in absorption.
D) on the inside of cell membranes.
E) mostly in muscle cells.
22) Microtubules
A) form cilia that aid in cell movement.
B) are composed of tubulin.
C) are the largest cytoplasmic fibers.
D) are hollow, filamentous structures.
E) All of the answers are correct.
23) Centrioles
A) hold the cell's ribosomes in place.
B) help move fluid through the cell.
C) direct the movement of DNA during cell division.
D) provide shape and stability to a cell.
E) are white blood cells outside of vessels.
24) Most of the ATP required to power cellular operations is made in the
A) nucleus.
B) endoplasmic reticulum.
C) ribosomes.
D) mitochondria.
E) Golgi apparatus.
25) Which does NOT accurately complete the sentence? One of the major functions of BOTH types of endoplasmic reticulum (ER) is the
A) storage of biomolecules.
C) transport of biomolecules.
B) storage of genetic material for the cell.
D) synthesis of biomolecules.
26) Which is NOT made in smooth or rough endoplasmic reticulum?
A) fatty acids
B) proteins
C) RNA
D) phospholipids
E) steroids
27) Which is NOT synthesized in the smooth endoplasmic reticulum (SER)?
A) proteins
B) steroids
C) lipids
D) fatty acids
E) All are synthesized in the SER.
28) Which consists of a network of intracellular membranes with attached ribosomes?
A) smooth endoplasmic reticulum
B) rough endoplasmic reticulum
C) nucleoli
D) Golgi apparatus
E) mitochondria
29) Which structure is NOT involved in storage?
A) storage vesicles
B) peroxisomes
C) mitochondrial cristae
D) lysosomes
E) All are involved in cellular storage.
30) The proteins synthesized in the rough endoplasmic reticulum are then sent to the
A) Golgi complex for packaging.
B) cell membrane for secretion.
C) lysosome for modification.
D) smooth endoplasmic reticulum for storage.
E) nucleus for cellular use.
31) You discovered a new cell that lacks lysosomes. This cell would NOT be able to
A) transport water-soluble molecules.
B) destroy H2O2
C) synthesize lipids.
D) digest cellular wastes and bacteria.
E) synthesize enzymes.
32) Which activates digestive enzymes inside lysosomes?
A) base B) air C) water D) enzymes E) acid 32)
33) Peroxisomes
A) use an enzyme to destroy H2O2 that is toxic to the cell.
B) are sites for synthesis of fatty acids, steroids, and phospholipids.
C) are responsible for the atrophy of unused muscles.
D) are a type of lysosome.
E) All of the answers are correct.
34) The number of mitochondria in skeletal muscle cells is the number of mitochondria in adipose (fat) cells.
A) less than B) greater than C) equal to
35) The control center for cellular operations is the
A) ribosomes.
B) mitochondria.
C) endoplasmic reticulum.
D) nucleus.
E) Golgi complex. 35)
36) The beta cells of the pancreas produce insulin, a protein hormone. Which organelle would be found in higher levels in the beta cells?
A) lysosomes B) mitochondria C) microvilli D) ribosomes
37) If the adrenal cortex produces lipid hormones such as aldosterone, which organelle would be higher in cells of the adrenal cortex?
A) Golgi apparatus
B) ribosome
C) rough endoplasmic reticulum
D) smooth endoplasmic reticulum
36)
E) mitochondria 37)
38) The nucleus stores DNA that encodes the sequence of which molecules?
A) phospholipids
B) carbohydrates
C) proteins
D) lipids
E) All of the answers are correct.
39) The term secretion refers to
A) the manufacture and assembly of a material.
B) the process by which a cell releases a substance into the extracellular space.
C) synthesis of a protein for export from the cell.
D) storage of a material, until it is time for it to leave the cell.
E) None of the answers describe secretion.
40) Which cellular organelle is considered the powerhouse of the cell because it produces most of the ATP?
A) mitochondria
B) Golgi apparatus
C) nucleus
D) ribosome
E) endoplasmic reticulum
41) Arrange the following events in protein secretion in the proper sequence.
1. The polypeptide chain enters the lumen of the endoplasmic reticulum.
2. A secretory vesicle is formed.
3. A transport vesicle is formed.
4. The polypeptide chain enters the lumen of the Golgi complex.
A) 1, 3, 2, 4 B) 1, 3, 4, 2 C) 3, 1, 4, 2 D) 1, 2, 3, 4 E) 4, 3, 1, 2
42) Movement of material between cells is known as the pathway.
A) cisendothelial
B) metacellular
C) paracellular
D) transendothelial
E) transcellular
43) Which is NOT a type of cell junction?
A) tight junctions
B) loose junctions
C) gap junctions
D) desmosomes
E) adherens junctions
44) The esophagus is a tube that carries food from the mouth to the stomach. It does not secrete any enzymes or absorb any nutrients, but it does need to stand up to significant friction and stress. The type of epithelium most likely lining the esophagus would be
A) stratified squamous epithelium.
B) transitional epithelium.
C) cuboidal epithelium.
D) simple columnar epithelium.
E) simple squamous epithelium. 44)
45) The type of protein found in gap junctions is the
A) claudin. B) integrin. C) occludin. D) connexin. E) cadherin.
46) Disappearance of which type of junction most likely contributes to the metastasis of cancer cells throughout the body?
A) tight B) anchoring C) gap
47) The types of junction proteins important in nerve growth and development are
A) immunoglobulin superfamily.
B) occludins.
C) claudins.
D) connexins.
E) integrins.
48) Which is NOT a primary tissue type?
A) osseous tissue
B) muscle tissue
C) neural tissue
D) epithelial tissue
E) connective tissue 48)
49) Which is NOT a function of epithelia?
A) movement
B) producing specialized secretions
C) storing energy reserves
D) providing physical protection
E) regulating exchange
50) Epithelial cells adapted for membrane transport of large quantities of materials, such as ions and nutrients, usually have on their apical surface.
A) flagella
B) lysosomes
C) cilia
D) microvilli
E) mitochondria 50)
51) Epithelia are connected to underlying connective tissues by
A) a basal lamina.
B) gap junctions.
C) the apical surface.
D) basal body.
E) desmosomes. 51)
52) Glands that secrete hormones into the blood are
A) unicellular glands.
B) exocrine glands.
C) endocrine glands.
D) mixed glands.
E) None of the answers are correct.
53) Exocrine glands
A) may make either mucous or serous secretions.
B) may work as single cells or as a multicellular organ.
C) may release their secretions through open tubes, called ducts.
D) release their secretions into the external environment.
E) All of the statements are true.
54) Every substance that enters or leaves the internal environment of the body must cross an epithelium.
A) True
B) False
55) Epithelia are more likely to develop genetic mutations associated with cancer because they divide frequently.
A) True
B) False
56) The function of microvilli on the apical membrane of transporting epithelia is to
A) increase the toughness of the cell.
B) increase the movement of extracellular fluid.
C) increase the cell's surface area.
D) increase the resistance of the cell to viruses.
E) allow the cell to move through a fluid medium.
57) The simple squamous epithelial lining of blood vessels is called
A) basolateral epithelium.
B) luteal cells.
C) endothelium.
D) the vasa recta.
E) None of the answers are correct.
58) Which tissue has extensive extracellular matrix?
A) epithelial
B) muscle
C) connective
D) neural
E) epithelial, neural, and muscle
59) Functions of connective tissue include
A) storing energy reserves.
B) transporting fluids and dissolved materials.
C) establishing a structural framework for the body.
D) providing protection for delicate organs.
E) All of the answers are correct.
60) Cells that store fat are called
A) liposomes.
B) melanocytes.
C) fibroblasts.
D) mast cells.
E) adipocytes. 60)
61) Loose connective tissue
A) attaches muscle to bone.
C) surrounds muscles and nerves.
62) Which is NOT a characteristic of plasma?
A) part of the ECF
B) the fluid portion of blood
B) supports small glands.
D) All of the answers are correct.
C) a dilute solution of ions and dissolved organic molecules
D) a watery extracellular matrix
E) a sticky solution containing glycoproteins and proteoglycans
63) The term meaning "programmed cell death" is
A) necrosis.
B) cytocide.
C) diuresis.
D) apoptosis.
E) oncogenesis.
64) The definition "less specialized cells that retain the ability to divide" applies to
A) nurse cells.
B) stem cells.
C) apoptosis.
D) gametocytes.
E) totipotent cells.
65) Groups of tissues that carry out related functions may form structures known as
A) organelles.
B) cells.
C) organs.
D) organisms.
E) Impossible to tell from the information given.
66) The heaviest organ in the body is the
A) skin.
B) stomach.
C) urinary bladder.
D) brain.
E) liver. 66)
67) This organelle is the site of most ATP synthesis in the cell.
A) endoplasmic reticulum
B) Golgi apparatus
C) lysosomes
D) mitochondria
E) peroxisomes 67)
68) These degrade long chain fatty acids and toxic foreign molecules.
A) endoplasmic reticulum
B) Golgi apparatus
C) lysosomes
D) mitochondria
E) peroxisomes
69) This is the digestive system of a cell, breaking down old organelles or bacteria.
A) endoplasmic reticulum
B) Golgi apparatus
C) lysosomes
D) mitochondria
E) peroxisomes
70) This modifies proteins and packages them into secretory vesicles for export from the cell.
A) endoplasmic reticulum
B) Golgi apparatus
C) lysosomes
D) mitochondria
E) peroxisomes
71) The simplest cell-cell junction is called a(n)
A) gap junction.
B) neuromuscular junction.
C) desmosome.
D) anchoring junction.
E) tight junction.
72) This junction contributes to the blood-brain barrier.
A) gap junction
B) anchoring junction
C) neuromuscular junction
D) desmosome
E) tight junction
73) These junctions can be cell-matrix junctions.
A) gap junction
B) connexin
C) neuromuscular junction
D) tight junction
E) anchoring junction
74) The loss of these junctions are a characteristic of cancer.
A) claudin constructed junction
B) gap junction
C) neuromuscular junction
D) tight junction
E) anchoring junction
75) This tissue is made up of adipocytes.
A) dense, regular connective tissue
B) fat
C) dense, irregular connective tissue
D) bone
E) cartilage
76) Fibroblasts that secrete collagen-rich matrix are the main cell type in this tissue.
A) loose connective tissue
B) fat
C) cartilage
D) blood
E) bone
77) Chondrocytes secrete a firm but flexible matrix to form what tissue?
A) bone
B) cartilage
C) fat
D) loose connective tissue
E) blood
78) An osteocyte is a main cell type in which tissue?
A) loose connective tissue
B) bone
C) blood
D) cartilage
E) adipose
79) Which plays a role in temperature regulation in infants?
A) collagen B) brown fat C) white fat D) bone E) cartilage
80) Nucleoli function in the production of
A) DNA that controls all cell functions.
B) RNA for ribosomes.
C) peroxisomes.
D) secretory vesicles.
E) proteins.
81) Cell membranes are said to be because they allow some substances to pass but not others.
A) structural
B) a physical barrier
C) hydrophilic
D) metabolically active
E) selectively permeable
82) The nucleus is surrounded by a(n)
A) plasmalemma.
B) nuclear envelope.
C) protein coat.
D) cell wall.
E) adhesion molecule.
83) Communication between the nucleus and cytosol occurs through
A) sodium channels.
B) plasmalemma.
C) nucleoli.
D) desmosomes.
E) nuclear pores.
84) Cells are transformed into specialized units during A) programed cell death.
B) transcription.
C) differentiation.
D) mitosis.
E) apoptosis.
85) The lining of the heart is called
A) secretory epithelium.
B) endothelium.
C) ciliated epithelium.
D) transporting epithelium.
E) protective epithelium.
86) is the extracellular component of connective tissues.
A) Mucous
B) Ground substance
C) Cartilage
D) Cytoplasm
E) Blood
87) The combination of fibers and ground substance in supporting connective tissues is known as
A) extracellular matrix.
B) blood.
C) cytoplasm.
D) mucous.
E) micelles.
88) The fluid substance of blood is called
A) interstitial fluid.
B) peroxide.
C) endothelium.
D) cytoplasm.
E) plasma. 88)
89) The study of tissue structure and function is called
A) differentiation.
B) histology.
C) physiology.
D) remodeling.
E) plasticity.
90) Structures composed of epithelial cells that produce secretions are called
A) micelles.
B) nuclear pores.
C) glands.
D) ducts.
E) cell junctions.
91) is a tissue that is modified to transmit chemical and electrical signals from one cell to another.
A) Neural tissue
B) Connective tissue
C) Exocrine tissue
D) Endothelium
E) Epithelia tissue
92) secretions are released onto an epithelial surface.
A) Microtubular
B) Endocrine
C) Exocrine
D) Nuclear
E) Hormonal 92)
93) secretions are released into interstitial space to diffuse into the blood.
A) Ribosomal B) Serous C) Mucous D) Exocrine E) Endocrine 93)
94) proteins extend all the way across the cell membrane.
A) Peripheral
B) Glycolipid
C) Nuclear
D) Cytoskeletal
E) Transmembrane
95) proteins attach loosely to other membrane proteins or polar regions of phospholipids.
A) Transmembrane
B) Glycolipid
C) Cytoskeletal
D) Nuclear
E) Peripheral
96) is a protective layer made up of mostly membrane carbohydrates.
A) Glycocalyx
B) Focal Adhesion
C) Cadherin
D) Epidermis
E) Connective tissue
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
97) Explain the relationship between microtubules, cilia, flagella, centrioles, spindle fibers, and the centrosome.
98) List the four major tissue types. Give an example and location of each.
99) Describe the structure of the cytoskeleton, and list its functions.
100) Define, compare, and contrast each term listed and explain how the terms are related to each other: rough endoplasmic reticulum, smooth endoplasmic reticulum, ribosomes, and Golgi Apparatus.
101) Sketch a cell membrane. Label at least three components and briefly explain what each one does.
102) Describe the composition and function of the extracellular matrix.
103) Define, compare, and contrast each term listed, and explain how the terms are related to each other: tendons, ligaments, cartilage, bone.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
104) If an animal cell lacked centrioles, it would not be able to
A) metabolize sugars.
B) undergo nuclear division.
C) maintain its balance.
D) synthesize proteins.
E) produce DNA.
105) Which cytoskeleton components are responsible for the movement of chromosomes during cell division?
A) microfilaments
B) microtubules
C) thick filaments
D) intermediate filaments
E) All of the answers are correct.
106) A flagellum moves a cell through a fluid medium. What moves the fluid medium across the surface of cells that are not free to move?
A) endoplasmic reticulum
B) ribosomes
C) cilia
D) thick filaments
E) centrioles
107) Which statement about mitochondria is FALSE?
A) Mitochondria can replicate themselves only when directed by the cell's nuclear DNA.
B) Mitochondria contain their own DNA and RNA.
C) The intermembrane space is used in the production of ATP.
D) Mitochondria are responsible for providing energy to the cell.
E) The outer mitochondrial membrane is responsible for its shape. 107)
108) Plasma is to blood as is to cytoplasm.
A) protein B) organelle C) inclusion D) cytosol E) serum
109) Examination of a sample of glandular cells shows an extensive network of smooth endoplasmic reticulum. Which would be a likely product of these cells?
A) protein (peptide) hormones
B) transport proteins
C) digestive enzymes
D) steroid hormones
E) protein antibodies
110) In a pancreatic cell producing digestive enzymes, you would expect to find a lot of
A) rough endoplasmic reticulum. B) smooth endoplasmic reticulum.
111) Chondrocytes are to cartilage as osteocytes are to
A) epithelium.
B) blood.
C) bone.
D) fat.
E) neural tissue.
112) The tissue(s) that is/are considered excitable because of the ability to generate electrical signals is/are called tissue.
A) muscle
B) neural
C) epithelial
D) muscle tissue and neural
E) muscle tissue, neural tissue, and epithelial
113) You are looking at a slide of an unknown organ that has an empty lumen with stratified squamous epithelium contacting the lumen. Deep to the epithelium is a basement membrane and then two layers of smooth muscle. Which organ would this most likely belong to and why?
A) The urinary bladder because it needs to stretch and constrict to store and eliminate urine.
B) The esophagus because it is a passageway that needs to move but not absorb food products.
C) The liver because it secretes enzymes and bile and needs to move them to the gallbladder.
D) The intestines because they need to move food along and absorb digested products.
114) A layer of proteoglycans and a network of filaments that prevents the movement of proteins and other large molecules from the connective tissue to epithelium describes
A) the reticular lamina.
B) the basal lamina.
C) areolar tissue.
D) endothelium.
113)
E) interfacial canals. 114)
115) The distinguishing characteristic of connective tissue is
A) that it is arranged in sheets of tissue that lie on body surfaces.
B) the presence of extensive extracellular matrix containing widely scattered cells.
C) that it is always dividing, constantly being replaced throughout the body.
D) the collagen fibers that offer support.
E) All of these characteristics help make connective tissue unique. 115)
116) Which type of connective tissue does NOT fit with the typical characteristic of a dense ground substance?
A) adipose B) tendons C) blood D) cartilage E) bone
117) Close examination of an organ shows a lining of several layers of cells. The layers do not contain any blood vessels, and one surface of the cells faces the internal cavity of the organ. This tissue is probably
A) muscle tissue.
B) fat tissue.
C) epithelium.
D) neural tissue.
E) connective tissue.
118) Increasing muscle mass and decreasing fat content in your body can increase ones use of energy. Why is this?
A) Muscle cells have more mitochondria than fat cells.
B) Fat is a connective tissue and not an excitable one.
C) Adipocytes contain more cytoplasmic inclusions.
D) Fat cells have no blood supply.
119) Microscopic examination of a tissue shows an open framework of fibers with a large volume of fluid ground substance and elastic fibers. This tissue would most likely have come from the
A) tissue that separates skin from underlying muscle.
B) inner wall of a blood vessel.
C) muscle
D) larynx.
E) bony socket of the eye.
120) Mature nerve cells are expected to lack which organelle(s)?
A) endoplasmic reticulum
B) Golgi bodies
C) nucleus
D) ribosomes
E) centrioles
121) Neurons in the CNS of the adult do not contain centrioles. What does that tell you about CNS neurons?
A) They do not replicate themselves.
C) They do not carry nerve impulses.
B) It does not tell you much of anything.
D) They do not produce any products.
122) Only totipotent stem cells are capable of producing new cells in an adult.
A) True
123) A lysosome is a(n)
A) membranous organelle.
B) transmembrane protein.
C) inclusion.
D) cytoskeletal protein.
E) glycolipid.
B) False 122)
124) Mitochondria are a(n)
A) membranous organelles.
B) transmembrane proteins.
C) inclusions.
D) cytoskeletal proteins.
E) glycolipids.
125) A ribosome is a(n)
A) membranous organelle.
B) transmembrane protein.
C) inclusion.
D) cytoskeletal protein.
E) glycolipid.
126) Cilia are a(n)
A) inclusions.
B) mitochondrial proteins.
C) adherens.
D) membranous organelles.
E) protein fibers.
127) The endoplasmic reticulum is a(n)
A) mitochondrial protein.
B) glycocalyx.
C) inclusion.
D) adheren.
E) membranous organelle.
128) This type of epithelia is found in the epidermis, esophagus, and mouth, and these stacked layers of cells prevent exchange, while they resist chemicals, bacteria, and other destructive forces.
A) exchange B) transport C) ciliated D) protective E) secretory
129) This type of epithelia actively and selectively regulates the exchange of nongaseous material, such as ions and nutrients, and can be regulated in response to various stimuli.
A) exchange B) transport C) ciliated D) protective E) secretory
130) This type of epithelia is made up of thin, flattened cells that allow the rapid passage of O2 and CO2 in and out of the lungs and of certain blood vessels.
A) exchange B) transport C) ciliated D) protective E) secretory
131) This type of epithelia has cells that produce a substance and release it, either onto a surface or into the blood.
A) exchange B) transport C) ciliated D) protective E) secretory
132) This type of epithelia is made up of cells with membrane extensions that beat in a coordinated fashion to move fluid and particles across the tissue.
A) exchange B) transport C) ciliated D) protective E) secretory
133) Referring to Figure 3.1, which letter represents the apical membrane? A) A B) B
134) Referring to Figure 3.1, which letter represents the basolateral membrane? A) A B) B
135) Referring to Figure 3.1, which letter represents the basal lamina?
136) Referring to Figure 3.1, which letter represents the plasma membrane? A) A
137) Referring to Figure 3.1, which letter represents the cytosol?
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
138) Draw a concept map for the types of cell junctions and the proteins that compose them.
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
139) Cancer is abnormal, uncontrolled cell division. Which property of epithelial tissues makes them more likely to develop cancer?
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
140) Describe the progression of a fertilized egg, from totipotent cell through pluripotent and multipotent stem cells. How might stem cells be of therapeutic value? What is plasticity?
141) Describe the anatomical and fluid compartments of the body. How do the lumens of hollow organs fit into these classifications? Which fluid-containing cavities are considered to be internal and which are external? Of those that are external, why are they external (give examples)? You may wish to design a flow chart to help answer this.
142) Describe the two general meanings of the term membrane, as used in biology. Which usage indicates layers of cells and which indicates layers of molecules?
143) Give three examples of structures whose formation involves molecular interactions that either increase or decrease contact with water molecules, explaining how they are similar and how they differ from each other. (Hint: They all involve molecules that have both polar and nonpolar portions.)
144) Your study partner is having difficulty understanding dense fibrous connective tissue, tendons, and ligaments. Explain to her how they are related to each other and how they are different from other categories of connective tissue.
145) Describe the difference between necrosis and apoptosis, and give specific examples of each.
146) If a person who has not exercised regularly begins a consistent exercise routine, he/she will notice that their metabolism will seem to increase as their endurance improves. Why is this?
147) What is the benefit of having some of the cellular organelles enclosed by a membrane similar to the cell (plasma) membrane?
148) Sketch a short series of simple columnar epithelial cells. Label each of the three different borders. Briefly explain the different kinds of activities that may go on at each border, and tell how their structures and junctions support these functions.
149) Which type of epithelium would you expect to find in the alveoli (air sacs) in the lungs? Defend your answer.
150) During a lab practical, Laurant examines a tissue that is composed of densely packed protein fibers that are running parallel and form a cord. There are few nuclei and no striations, and there is no evidence of other cellular structures. Laurant identifies the tissue as skeletal muscle. Why is Laurant's choice wrong, and which tissue is he probably observing?
151) Cancer is not one disease but a group of related diseases, caused by abnormal genes, environmental factors, and/or viral infections. Describe the basic common characteristics of cancers, including the role of anchoring junctions and proteases. What is a tumor? What is metastasis? Is cancer usually considered to be contagious? Explain.
152) In typical women of reproductive age, the epithelial cells lining the uterus (the endometrium) die and are shed from the body roughly once every month, in the process of menstruation. The triggers in this process include chemical (hormonal) changes and contraction of the blood vessels in the lining. Cell death may be a result of either apoptosis or necrosis. Describe the characteristics of each process. Develop an argument for classifying the process of menstruation as an example of apoptosis, and then argue for classifying it as necrosis. Which is correct?
153) The most common types of cancer in America include colon cancer, skin cancer, breast cancer, cervical cancer, and prostate cancer. What do all of these cancers have in common and why are they so prevalent in our society?
154) Apoptosis and necrosis are described as the two ways cells die. Which one is "messy"? Which is "tidy"? Explain. Why do these forms of cell death exist? What are some advantages and/or disadvantages of each? Use the lining cells of the digestive tract in an example of an advantageous process.
155) A. Define stem cells and differentiation, and describe the different types and the extent to which they are present d the life of an individual (include the fertilized egg as well as the adult that eventually results).
B. Which of the four tissue types contain populations of stem cells of known function, and what is that function? types of tissue have stem cells of unknown function? Do any types of tissue lack stem cells?
C. How do fully differentiated cells differ from stem cells? How can stem cells be used in medical treatment? Give examples.
156) Stem cell research has become a political topic in the last few decades. Explain why the research is being done, why some cells are favored for this research over others, and what the factors are that cause some people not to support this type of research. Are any alternatives available that are less opposed?
157) Nervous tissue includes two types of cells: neurons and glial cells. Glial cells are mitotic, whereas neurons are not (except the small population of stem cells). Which type of cell is most likely to be involved in brain cancer, and why?
158) Cell membranes are made up of lipid, protein, and carbohydrate in relative amounts that vary according to cell type. Describe the relative proportions of these substances in three structures, and relate these differences to cell function where possible.
159) Nutrients undergo the last stages of digestion by enzymes located on the cells of the small intestine; then the nutrients are absorbed by these same cells by way of various membrane transport processes. Adipose cells absorb and store excess food energy in the form of fat. You and the other students in the physiology lab you are taking are doing an analysis of cell membrane composition, on unknown animal tissue samples labeled A and B. All lab groups determined that sample A contained, on average, 81% protein, 18% lipid, and 1% carbohydrate. Sample B contained 85% lipid, 10% protein, and 5% carbohydrate. Sketch a graph of the class data. You now have to make a logical conclusion as to which sample is more likely to be intestine and which is adipose tissue. What do you conclude, and why?
Answer Key
Testname: UNTITLED22
1) C
2) C
3) A
4) D
5) B
6) E
7) B
8) E
9) D
10) C
11) E
12) A
13) E
14) A 15) E
16) D
17) B
18) D
19) D
20) B
21) C
22) E
23) C
24) D
25) B
26) C
27) A
28) B
29) C
30) A
31) D
32) E
33) A
34) B
35) D
36) D
37) D
38) E
39) B
40) A
41) B
42) C
43) B
44) A
45) D
46) B
47) A
48) A
49) C
50) D
Answer Key
Testname: UNTITLED22
51) D
52) C
53) E
54) A
55) A
56) C
57) C
58) E
59) E
60) E
61) B
62) E
63) D
64) B 65) C
66) A
67) D
68) E 69) C
70) B 71) A
72) E
73) E
74) E
75) B 76) A
77) B
78) B
79) B
80) B
81) E
82) B
83) E
84) C
85) B
86) B
87) A
88) E
89) B
90) C
91) A
92) C
93) E 94) E
95) E 96) A
97) Microtubules are a cytoskeletal protein made of tubulin. Microtubules form a major component of the internal scaffolding of the cell. Microtubules can also be assembled into cilia and flagella, which are organelles that produce cell-generated movements, and into centrioles and spindle fibers. Centrioles produce the spindle fibers, which are responsible for changing the position of chromosomes during nuclear division. Centrioles are part of a larger structure known as the centrosome, which also includes a darkly staining material and acts as the cell's microtubule organizing center.
98) See Table 3.4 and the "Tissues of the Body" section in the chapter.
99) The cytoskeleton consists of actin microfilaments, intermediate filaments, and microtubules and forms a scaffold throughout the cytoplasm. An interesting feature is that some of the proteins are relatively fixed in position, whereas others can be rapidly assembled or disassembled as necessary. The functions include providing mechanical strength and shape, stabilizing position of organelles, intracellular transport system, functional linkage to other cells and to extracellular space, and cell-generated movements.
100) All are structures involved in synthesis of biomolecules. All but ribosomes are membranous structures. Ribosomes may be free or attached to ER, making it rough. See Figure 3.4 in the chapter.
101) See Figure 3.2
102) In any tissue, the extracellular matrix consists of two basic components: proteoglycans and insoluble proteins. The matrix plays an important role in processes ranging from growth and development to cell death. The matrix aids in cell communication with its environment by attaching to the cell membrane or cytoskeleton.
103) Each term is a type or subtype of connective tissue. Tendons attach skeletal muscle to bone, whereas ligaments connect bone to bone. Cartilage and bone together are structurally supportive tissues. See Figure 3.12 and 3.13 in the chapter.
104) B
105) B
106) C 107) A 108) D
D 110) A 111) C 112) D 113) B 114) B
115) B 116) C
117) C
118) A
119) A
120) E
121) A
122) B
123) A
124) A
125) C
126) E
127) E
128) D
129) B
130) A
131) E
132) C
133) B
134) E
135) C
136) D
137) A
138) This is discussed in the "Tissues of the Body" section of the chapter and shown in Figure 3.8a.
139) Epithelial tissues contain a population of dividing cells, which divide at a moderate rate.
140) This is discussed in the "Tissue Remodeling" section of the chapter.
141) The anatomical compartments are the cranial cavity, containing the brain; the thoracic cavity, containing the heart and lungs; and the abdominopelvic cavity, containing organs of the digestive, urinary, and reproductive systems. The fluid compartments are the intracellular fluid (inside the cells) and the extracellular fluid (outside the cells). The extracellular fluids are found in the interstitial fluid between cells and the plasma of the blood, which is in the lumen of the circulatory system. Lumens of hollow organs such as the digestive and urinary tracts are part of the external environment, whereas the intracellular and interstitial fluids are internal. The lumen of the circulatory system is also internal. External lumens are those that open to the outside environment. These openings include the mouth, nostrils, anus, urethral, and vaginal orifices.
142) Prior to the use of microscopes, membranes were simply thin, flexible layers of cells that separated large compartments or lined large cavities. When microscopic study of cells allowed visualization of the cell envelope and organelles, the term membrane was additionally applied to thin layers of molecules.
143) Phospholipids have a polar portion that is attracted to water and a nonpolar portion that repels water. The molecules orient in water such that water is excluded from contacting the nonpolar portions. This is seen in: the bilayer arrangement of phospholipids in cell membranes, in which hydrophobic tails are in the middle of the layer; micelles, in which a single layer of phospholipids forms a sphere with the hydrophobic tails in the middle; and liposomes, which are hollow spheres made from phospholipid bilayers that can be filled with water-soluble molecules.
144) Dense fibrous connective tissue is a category of connective tissue, distinct from loose, adipose, blood, bone, and cartilage. It is not as dense as cartilage and bone but is denser than the other types listed. Like loose connective tissues, fibroblasts are the primary cell type, but unlike loose, the matrix consists of relatively more protein fibers and less ground substance. Like bone and cartilage, the fibers are primarily collagen. The fibers can be arranged randomly (irregular) or parallel to each other (regular). Tendons and ligaments are both composed of dense fibrous connective tissue. Tendons attach muscles to bones, whereas ligaments attach bones to bones; tendons lack elastic fibers, but they are present in ligaments; therefore ligaments are slightly stretchy.
145) Necrosis is cell death as a result of damage from toxins, physical trauma, or lack of oxygen; damaged cells release chemicals that may damage neighboring cells. An example is death of skin cells as a result of sunburn. Apoptosis is programmed cell death, which is an internally regulated process and does not involve neighboring cells unless they too are so programmed. An example is the loss of skin webbing between fingers and toes in a fetus.
146) Metabolism will increase with endurance because the number of mitochondria will increase with consistent exercise. The increase in mitochondria will improve endurance and increase metabolism of glucose because they will be metabolizing more glucose into ATP.
147) The isolation of the internal contents of membrane-bound organelles allows them to manufacture or store secretions, enzymes, or toxins that could adversely affect the cytoplasm in general. Another benefit is the increased efficiency of having specialized enzyme systems concentrated in one place, for example, those necessary for energy production in the mitochondrion In addition, the membranes themselves serve as "workspace," allowing the anchoring of enzymes or other proteins into a stabilized location.
148) This is discussed in the "Tissues of the Body" section of the chapter.
149) Since gases must diffuse across the alveoli and associated capillaries you would expect to find exchange epithelia, composed of very thin cells (simple squamous epithelium). Thicker types of epithelial cells would slow the process of gas diffusion to and from the blood.
150) Skeletal muscle tissue is made up of densely packed fibers running in the same direction, but since muscle fibers are composed of cells, they would have many nuclei and mitochondria. Skeletal muscle also has an obvious banding pattern or striations due to the arrangement of the actin and myosin filaments within the cell. Laurant is probably looking at a slide of tendon (dense connective tissue).
151) Cancer results when cells begin to divide and grow and do not respond to normal controls that would limit their growth. Anchoring junctions eventually fail to keep the cancer cells together, allowing them to spread to other organs where they continue to grow uncontrolled. Some cancer cells secrete proteases that improve their ability to spread or metastasize. A tumor is a lump of cancerous cells. Cancer is usually not contagious, being caused instead by genetic mutations in an individual or exposure to environmental factors by that individual; exceptions are cancers caused by viruses, which are believed to be the minority.
152) (Note to instructor: If students have not yet studied the reproductive system, they may not be able to answer the final question, therefore it could be omitted.) Necrosis is cell death as a result of damage from toxins, physical trauma, or lack of oxygen; damaged cells release chemicals that may damage neighboring cells. Apoptosis is programmed cell death, which is an internally regulated process and affects only the cell it occurs within. Menstruation may result from necrosis if the causative factor is changes in blood flow to the endometrium such that the oxygen supply is inadequate. Menstruation may result from apoptosis if it results from hormonal changes that directly kill the cells. While menstruation is a normal event and removes unneeded cells (characteristics of apoptosis), it results directly from the decrease in circulation, causing the cells to die from lack of oxygen; thus it is an example of necrosis.
153) All of these structures have epithelial tissue that is reproducing at a rapid rate. Because they undergo mitosis so often if a failure of apoptosis occurs or if a mutation alters the DNA of one of the cells, the new copies of the existing cells will cause an increase in the cancerous cells at a much faster rate than in other tissues that divide at a much slower rate.
154) Necrosis is a result of damage to cells. The cells swell and rupture, and the enzymes that are released cause damage to other cells in the area; hence the descriptor "messy." Necrosis has the disadvantage of damaging cells that might otherwise have survived unscathed. Necrosis is not an advantageous process, but it is unavoidable because trauma to cells is unavoidable; we all get hurt sometimes. Apoptosis is "tidy" in that the cells do not rupture and release damaging enzymes; instead the cell breaks up into membrane-surrounded pieces that are consumed by immune cells. Apoptosis is advantageous in that it can shape a structure such as fingers and toes during development. In the case of the digestive tract, the harsh chemical environment would lead to frequent necrosis if it weren't for the programmed apoptosis occurring every day or so.
155) A. Stem cells are cells that are mitotic and not fully differentiated. Differentiation is the process cells undergo as they become more and more specialized in structure and function as is typical of the specific tissues they compose. The fertilized egg and the cells resulting from the first few cleavage divisions after fertilization are totipotent, which means they can ultimately produce all the types of cells in an adult. Within the first week after conception, the cells begin differentiation and become capable of producing many types of cells but not all. These cells are pluripotent. By adulthood, stem cells can be described as multipotent, which are stem cells that can produce many of the cell types in a specific tissue, and committed stem cells, which can only become one specific cell type within that tissue.
B. Epithelial and connective tissues have active populations of multipotent stems cells, which replace cells lost to damag normal turnover. Muscle and nervous tissues contain stem cells but appear to be unable to replace lost cells. They were thought to lack stem cells altogether.
C. Once cells are fully differentiated, they can no longer divide to produce more cells. Disease conditions or injuries tha result in cell loss may be remedied by treatment with appropriate stem cells. Examples are neurological injuries and diseases marked by irreversible damage to cells that cannot (yet) be replaced by new cells.
156) Stem cell therapy may remedy previously untreatable diseases and conditions such as those involving brain and spinal injury. It has become political because one source of stem cells that are highly desirable for research is those removed from human embryos and fetuses. These cells are less differentiated and therefore more likely to be able to yield the specific types of mature cells desired. Many people opposed to abortions of human pregnancies are opposed to the use of human embryos and fetuses as a source of stem cells because these embryos and fetuses are destroyed in the process. Use of umbilical cord blood from live births is less opposed, though these cells are somewhat limited in the types of cells they can produce and therefore may not be valuable for treating as large a variety of diseases and injuries.
157) Cancer results from uncontrolled cell division in mitotic cells. Therefore, glial cell cancers (gliomas) are the most common type of nervous system cancers, as they have the most mitotic activity.
158) (Note to instructor: This may be a good question to use on a comprehensive final exam, as it ties together basic membrane composition with cell functions revealed in later chapters.) See Table 3.1 in the chapter. Red blood cells have nearly equal amounts of protein and lipid, with a small amount of carbohydrate, in this ratio of protein:lipid:carbohydrate: 49:43:8. Myelin is almost all lipid, followed by protein and carbohydrate in this ratio of lipid:protein:carbohydrate: 79:18:3. In later chapters on the nervous system, it will be seen that this preponderance of lipid results in electrical insulation, which is one of the main functions of myelin. The inner mitochondrial membrane is mostly protein, in this ratio of protein:lipid:carbohydrate: 76:24:0. This reflects the function of this membrane in chemical synthesis that relies on a variety of protein enzymes.
159) A bar graph would be appropriate, as in the figure below. The presence of digestive enzymes and membrane transporters in small intestine cells indicate there should be a significant amount of protein present. Adipose cells, on the other hand, are relatively inactive and can passively absorb lipids by way of simple diffusion through the membrane phospholipids. Adipose tissue is expected, therefore, to consist primarily of lipids. Sample A is most likely s intestine, and sample B adipose.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Energy is defined as
A) the light and heat from the sun.
C) the capacity to do work.
B) doing tasks that make you tired.
D) using glucose to synthesize ATP.
2) The general term that describes energy stored in chemical bonds is
A) kinetic energy.
B) entropy.
C) bioenergetics.
D) potential energy.
E) thermodynamics.
3) According to the second law of thermodynamics,
A) entropy increases in living systems without the input of energy.
B) energy can be converted, but not be created nor destroyed.
C) the total amount of energy in the universe never changes.
D) entropy decreases in living systems that are not receiving energy.
4) Chemical reactions in a living system function to
A) transfer energy from one molecule to another.
B) create new energy.
C) use energy stored in a molecule.
D) A and C
E) A, B, and C.
5) The of glycogen from many glucose molecules is an reaction.
A) synthesis, endergonic
B) decomposition, endergonic
C) decomposition, neither endergonic nor exergonic
D) synthesis, exergonic
6) Activation energy is
A) the energy required for an endergonic reaction.
B) the energy lost or gained in a reaction.
C) required to change an endergonic reaction to an exergonic reaction.
D) the energy required to bring molecules into a position where they can interact.
7) A reversible reaction is one where
A) a reaction between products is unlikely due to the high activation energy.
B) there are large changes in the net free energy from substrate to product.
C) there are small changes in the net free energy from substrate to product.
D) there is no change in the net free energy from substrate to product.
8) Isozymes are
A) inorganic molecules that bind to and activate enzymes.
B) the inactive form of an enzyme.
C) enzymes with the same structure that catalyze different reactions.
D) enzymes with a slightly different structure that catalyze the same reaction.
9) Enzymes increase reaction rate by
A) converting an endergonic reaction to an exergonic reaction.
B) lowering the activation energy of a reaction.
C) increasing the free energy in the products.
D) raising the activation energy of a reaction.
10) When a chemical reaction is in equilibrium,
A) the reaction has stopped.
B) there is no net change in the amount of substrates or products.
C) the reaction is proceeding at its maximum rate.
D) there are equivalent amounts of substrates and products.
11) Organic molecules that act as receptors and carriers for the cleaved portion of the substrate are
A) coenzymes. B) isoenzymes. C) vitamins. D) modulators.
12) The activity of an enzyme is changed by factors such as feedback inhibition; this factor is referred to as a(n)
A) modulators.
B) common bond.
C) product.
D) isozyme.
E) specificity.
13) The addition of a phosphate group to a substrate is called . The enzyme that catalyzes this reaction is referred to as a
A) proteolysis, phosphatase
C) proteolysis, kinase
B) phosphorylation, kinase
D) phosphorylation, phosphatase
14) Phosphate groups may be transferred from one molecule to another during
A) exchange reactions only.
B) dehydration reactions only.
C) addition reactions only.
D) addition and exchange reactions.
E) hydrolysis reactions only. 14)
15) When an enzyme's activity is inactivated by heat or a change in pH, the enzyme is said to be
A) tertiary.
B) broken.
C) denatured.
D) toxic.
E) conjugated.
16) A competitive inhibitor binds to
A) the active site.
B) the product.
C) a region of the enzyme other than the active site.
D) the surrounding tissue.
E) the substrate.
17) An allosteric modulator binds to A) the product.
B) a region of the enzyme other than the active site.
C) the substrate.
D) the active site.
E) the surrounding tissue.
18) An enzyme that transfers chemical groups among substrates is a A) hydrolase.
B) lipase.
C) transferase.
D) ligase.
E) kinase.
19) An enzyme that joins two substrates using energy is a A) hydrolase.
B) lipase.
C) transferase.
D) ligase.
E) kinase.
20) An enzyme that adds or subtracts water molecules is a A) hydrolase.
B) lipase.
C) transferase.
D) ligase. E) kinase.
21) An enzyme that transfers phosphates from ATP to a substrate molecule is a A) ligase.
B) kinase.
C) transferase.
D) lipase.
E) hydrolase. 21)
22) A molecule that loses electrons during a reaction is A) oxidized. B) dehydrated. C) reduced. D) hydrated. 22)
23) The binding sites of enzymes are
A) not necessarily involved in a reaction.
B) products of an enzymatic reaction.
C) regions of an enzyme that are involved in bringing substrates together. D) bonds between the substrate and certain amino acids. 23)
24) When an enzyme is working as fast as it can because its active site is continually refilled with substrate, the condition is referred to as
A) allosteric modulation.
B) saturation.
C) specificity.
D) equilibrium.
E) the Ricardo-Mertz phenomenon.
25) Which of these results in a REDUCED molecule?
A) gain of electrons
C) gain of phosphate
26) End-product inhibition describes the process whereby
B) loss of electrons
D) loss of phosphate
A) increasing amounts of substrate decrease activity of the enzyme.
B) increasing amounts of product decrease activity of all nearby enzymes.
C) increasing amounts of product decrease activity of the enzyme.
D) decreasing amounts of product decrease activity of the enzyme.
E) decreasing amounts of substrate decrease activity of the enzyme.
27) When energy is released during catabolism, it is temporarily trapped in high-energy bonds or electrons of certain compounds. Which of the following is NOT associated with carrying energy?
A) ATP B) NADH C) NADPH D) DNA E) FADH2
28) Compartmentation refers to
A) grouping related enzymes into specific organelles.
B) pairing together isozymes that perform similar reactions.
C) separating substrates into chemical classes.
D) dividing metabolic reactions into groups for better understanding.
29) Aerobic metabolism of glucose
A) produces more ATP per glucose than anaerobic pathways.
B) requires oxygen.
C) is the fastest way to produce glucose.
D) A and B
E) A, B, and C.
30) The reactions of glycolysis occur in the cell's ; the reactions of the citric acid cycle occur in the
A) cytosol, mitochondria
C) cytosol, cytosol
B) mitochondria, mitochondria
D) mitochondria, cytosol
31) In the aerobic metabolism of glucose, acts as the final acceptor of electrons.
A) carbon dioxide
B) oxygen
C) lactate
D) ATP
E) water
32) The explanation for how ATP bonds are actually formed during oxidative phosphorylation is called
A) the Krebs hypothesis.
B) the chemiosmotic theory.
C) Murphy's law.
D) the proton principle.
E) the second law of thermodynamics.
33) For each mitochondrial NADH molecule that moves through the electron transport system, what is the potential yield of ATP molecules?
3.5
2
34) What is the potential yield of ATP molecules for each FADH2 molecule entering the electron transport system?
2
3
35) Why is there a range of 30-32 ATP molecules produced from one glucose molecule?
A) Sometimes the electron transport system is more efficient than other times.
B) Individual variation is normal among cells.
C) The NADH molecules produced during glycolysis are in the cytoplasm; occasionally, electrons are carried by the lower energy FADH2 instead of NADH.
D) Any of these answers may work under different cellular conditions.
36) Which can serve as substrates for ATP production?
A) amino acids
B) glucose
C) fatty acids
D) A and B
E) A, B, and C
37) ATP synthase transfers the energy of the H+ ions to the high-energy phosphate bond of .
A) kinetic, NADH
B) potential, ATP
C) kinetic, ATP
D) potential, NADH
E) None of the answers are correct.
38) An example of transamination is
A) finding a brand new sports car in your driveway with your name on it.
B) removing a phosphate group from a molecule.
C) removing an amino group from one molecule and binding it to a different molecule.
D) removing an amino group and putting it into the bloodstream for the kidneys to discard.
39) The process of forming mRNA is called
A) ribolation.
B) replication.
C) transcription.
D) translation.
E) protein synthesis.
40) After forming a complex with the ribosome, mRNA interacts with a third molecule. This molecule is called
A) tRNA.
B) rough ER.
C) DNA.
D) an amino acid.
E) rRNA.
41) The TAC sequence of DNA is the of a coding sequence that is preceded by the that regulates transcription.
A) stop, intron
C) stop, promoter region
B) start, promoter region
D) start, intron
42) All of the triplet codons needed to produce one functional piece of RNA are found in one
A) codon.
B) gene.
C) anticodon.
D) chromosome.
E) None of the answers are correct.
43) Information stored in the nucleus is translated into
A) phospholipids.
B) proteins.
C) lipids.
D) carbohydrates.
E) None of the answers are correct.
44) Transcription occurs in the of the cell.
A) smooth endoplasmic reticulum
B) cytoplasm
C) plasma membrane
D) nucleus
E) Golgi apparatus
45) The enzymes that synthesize mRNA from the DNA template are called
A) ATP synthases.
B) ribonucleases.
C) RNA polymerases.
D) DNA polymerases.
E) lactate dehydrogenases. 45)
46) To activate a regulated gene, the formation of mRNA is by the binding of to the promoter.
A) induced, transcription factors
C) induced, translation factors
B) repressed, transcription factors
D) repressed, translation factors 46)
47) Once synthesized, the of mRNA are removed through , which results in the formation of the coding sequence of a protein.
A) intron, RNA interference
C) exon, alternative splicing
47)
B) exon, RNA interference
D) intron, alternative splicing
48) The tRNA molecule contains the three-base sequence called the A) codon. B) anticodon. C) aminocodon. D) semicodon.
49) A signal sequence localizes a newly-synthesized protein to the A) endoplasmic reticulum. B) nucleus. C) nucleous. D) nuclear membrane. E) cytosol.
50) Following post-translational modification, any misfolded protein will be destroyed by A) proteosomes. B) chaperones. C) ribonucleases. D) methylation.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the specific enzyme to its class.
51) synthetase
52) dehydrogenase
53) dehydratase
54) lipase
55) kinase
56) aminase
57) deaminase A) lyase B) ligase C) transferase D) oxidoreductase
In the reaction shown, identify the role of each of the participants.
CARBONIC
CO2 + H2O ANHYDRASEH2CO3
58) CO2 + H2O
59) carbonic anhydrase
60) H2CO3
E) hydrolase
A) product(s)
B) substrate(s)
C) enzyme
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
61) A molecule positioned on the high-concentration side of a concentration gradient stores energy.
A) chemical
B) kinetic C) potential
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
62) A chemical reaction that can proceed in both directions is called a reaction. 62)
63) Chemical reactions that require an input of energy are said to be 63)
64) Chemical reactions that release energy are said to be 64)
65) Metabolic intermediates use bonds to transfer energy to the high-energy bonds of ATP, NADH, FADH2 or NADPH. 65)
66) The rates of chemical reactions that occur in the human body are controlled by a particular type of proteins called 66)
67) A certain molecule that participates in more than one biochemical pathway and acts as a branch point for channeling substrate in one direction or another is called a . 67)
68) describes how much product is generated or substrate destroyed within a period of time. 68)
69) The availability of determines if pyruvate continues into the citric acid cycle. 69)
70) Glucose is phosphorylated to with a phosphate from 70)
71) The activity of metabolic pathways is influenced by the ratio of 71)
72) In the process of a phosphate group is attached to a molecule. 72)
73) generated in the enters the electron transport system to generate 2.5 ATP molecules. 73)
74) Energy released by electrons moving through the electron transport system is stored as by H+ ions concentrated in the 74)
75) The electron transport system is located in the and includes enzymes and iron-containing proteins known as 75)
76) During the synthesis of proteins, amino acids are assembled in the proper sequence because the tRNA molecules that bring them to the ribosome have a(n) that is complementary to a specific codon in the mRNA. 76)
77) mRNA is created in a process called It then leaves the and enters the cytosol to direct , the assembly of amino acids into protein. 77)
78) Amino acids are carried to the ribosomes to be incorporated into polypeptide chains by . 78)
79) The enzyme and ions are required for the synthesis of mRNA. 79)
80) A molecule of consists of all the codons needed to produce a specific polypeptide chain at the ribosome. 80)
81) Ribosomes are composed of protein and 81)
82) RNA is usually a strand. 82)
83) is a process which blocks translation. 83)
84) Genes that are always being read and converted to RNA messages are 84)
85) Transcription factors are proteins whose binding to the region for a gene can (increase) of that gene. 85)
86) The contains the coding sequence of the gene. 86)
87) The is the portion of the mRNA that contains the coding sequence of the gene. 87)
88) The peptide bond formed between amino acids occurs as a consequence of 88)
89) Protein folding can take place spontaneously or with . 89)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
90) Compare and contrast potential energy with kinetic energy.
91) Define the law of mass action.
92) What are the advantages of using ATP as the energy-transferring molecule in a cell?
93) Describe the four types of enzymatic reactions.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
94) An exergonic chemical reaction
A) requires an enzyme in order to overcome the activation energy.
B) converts substrates into products that have more free energy.
C) releases energy as the reaction progresses.
D) requires the input of energy. 94)
95) How would the lack of a required cofactor for an enzyme affect that enzyme's function?
A) The enzyme would function more quickly.
B) The enzyme's function would not be altered.
C) The enzyme would function more slowly.
D) The enzyme would not be able to function. 95)
96) Enzymes are often useful as diagnostic tools. How?
A) Enzymes destroy damaged cells so X-rays reveal smaller body organs.
B) Enzymes destroy pathogenic bacteria so blood levels of bacteria decline.
C) Damaged cells release enzymes into the blood that can be detected.
D) The liver releases enzymes that accumulate in the urine.
97) The rate of product formation by an enzyme-catalyzed reaction would be increased by
A) adding more substrate molecules.
B) decreasing the number of substrate molecules.
C) decreasing the number of enzymes.
D) adding more product molecules.
98) Changes in environmental pH or temperature will cause the reaction rate for an enzyme to
A) decrease.
B) increase.
C) either increase or decrease depending upon enzyme properties.
D) not change.
99) Cells normally regulate the rate of an enzymatic reaction by
A) changing the concentration of an enzyme.
B) allowing all metabolic enzymes to be found throughout the cytosol.
C) raising their temperature to 110° F.
D) increasing reaction rate as the concentration of product increases.
100) Increasing will decrease the amount of mRNA within a cell for a constitutively active gene.
A) siRNA concentration
B) RNA polymerase activity
C) ribonuclease activity
D) A and C
E) A, B, and C
101) In order to slow generation of product from a particular biochemical pathway within a cell, the intermediates formed by that pathway
A) are removed from the cell more quickly. B) become toxic to the cell.
C) accumulate inside the cell.
D) are rapidly converted into.
102) Which is a key intermediate of glucose catabolism to the citric acid cycle?
A) ATP
B) oxygen
C) pyruvate
D) glucokinase
E) lactate
103) The net energy yield for the anaerobic metabolism of one glucose molecule is
A) 2 ATP, 6 NADH, and 2 FADH2
B) 2 ATP and 2 FADH2.
C) 2 ATP and 0 NADH.
D) 2 ATP and 2 NADH.
E) 0 ATP and 2 NADH. 103)
104) Inside the matrix of the mitochondria, pyruvate
A) gains a carbon in its conversion to acetyl CoA.
B) requires the vitamin pantothenic acid for its conversion to acetyl CoA.
C) is converted to lactate under anaerobic conditions.
D) is converted to acetyl CoA which requires energy from an NADH.
105) NADH is produced from each reaction EXCEPT during
A) the citric acid cycle.
B) anaerobic glycolysis.
C) the conversion of pyruvate to acetyl CoA. D) aerobic glycolysis.
106) Oxidative phosphorylation occurs ; the beneficial end product is .
A) in the mitochondria due to the electron transport system, CO2
B) in the cytosol just inside the plasma membrane, ATP
C) twice during the citric acid cycle, ATP
D) in the mitochondria due to the electron transport system, ATP
E) in the cytosol just inside the plasma membrane, H2O
107) The protein in the mitochondria that captures the kinetic energy of moving H+ ions and converts it to the stored energy of ATP is called
A) lactate dehydrogenase.
C) ATP synthase.
B) oxidative phosphorylase.
D) glucokinase.
108) What happens to the oxygen that is metabolized within the mitochondria?
A) The oxygen acts as a coenzyme in the production of ATP.
B) The oxygen is converted to CO2.
C) The oxygen is incorporated into organic molecules during cellular metabolism.
D) The oxygen is combined with hydrogen to form water.
E) The oxygen is converted to CO2 and is combined with hydrogen to form water.
109) What is the result of alternative splicing of mRNA?
A) Genes may be mutated.
B) The DNA can be replicated.
C) A new gene can be produced.
D) Isozymes may be produced from a single gene.
E) Proteins can isomerize.
110) Transcription of the DNA triplet sequence ATC yields A) UAG. B) UTC. C) ATC. D) TAG.
110)
111) The mRNA sequence CAU will bind to the tRNA sequence A) UAC. B) GUA. C) CAT. D) CAU. 111)
112) The template strand of DNA
A) serves as a guide for mRNA synthesis.
B) is alternatively spliced to generate the exon.
C) includes the base uracil.
D) is not involved in mRNA synthesis. 112)
113) During starvation, steroid hormones stimulate the transcription of genes for lipid metabolism in their target cells. This would be an example of control by
A) negative feedback.
B) alternative splicing.
C) repressors.
D) positive feedback.
E) inducers.
114) If the enzyme RNA polymerase was completely inhibited within a cell, it could not
A) form spindle fibers.
B) form complementary sequences of DNA.
C) form a new nuclear membrane during cell division.
D) form proteins.
E) link pieces of DNA together.
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
115) Regulatory-protein transcription factors bind to and activate , which tells the RNA polymerase 115)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
116) Briefly describe oxidation-reduction reactions. What does it mean for a molecule to be reduced or oxidized?
Identify and explain the mnemonic device provided in the text for oxidation and reduction reactions. See if you can make one up yourself.
117) Identify which statement(s) is/are correct. Explain what is wrong with each incorrect statement.
A. A chemical reaction is at equilibrium when there is no further change in substrates.
B. A chemical reaction is at equilibrium when the amounts of substrates and products no longer change.
C. A chemical reaction stops when it reaches equilibrium.
D. A chemical reaction is at equilibrium when the amount of substrate equals the amount of product.
118) Identify which statement(s) is/are correct. Explain what is wrong with each incorrect statement. Explain when ch reactions continue and when they stop.
A. A chemical reaction proceeds until the enzyme molecules are all consumed.
B. A chemical reaction proceeds until the substrate molecules are all consumed.
C. A chemical reaction proceeds until equilibrium is established.
D. A chemical reaction proceeds until all the product molecules are removed.
119) Think about these two chemical reactions. Identify each statement following as true or false, and clarify as neede
A + B → C
C → A + B
A. The enzyme catalyzing the formation of C must be different from that catalyzing the breakdown of C.
B. The enzyme catalyzing the formation of C must be the same as that catalyzing the breakdown of C.
C. Only one of the reactions could occur in a given cell or system.
D. Both reactions must be occurring in an equilibrium situation.
E. Equilibrium is always achieved in a chemical reaction.
F. Equilibrium can be prevented from occurring by constantly removing the product of either reaction.
G. An equilibrium, once established, cannot be disturbed.
120) Explain how enzymes can be useful in the diagnosis of disease, giving specific examples. Is the change in enzyme concentration a direct or indirect result of the disease?
121) Based on the facts about chemical equilibrium in animal systems, indicate for each summary reaction below if it reversible or irreversible (do not worry about balancing the reactions). Explain the lack of reversibility. In what k system would the reaction(s) you selected as irreversible be reversible? Explain.
A. C6H12O6 → CO2 + H2O
B. ADP + Pi → ATP
C. H2O + CO2 → H2CO3
122) Explain what a concentration gradient is and how it assists a cell in doing its work.
123) Carbonic acid is generated by bubbling CO2 into a beaker of water. If it took 5 minutes for this reaction to reach equilibrium, how would the results differ if the enzyme carbonic anhydrase was added to the beaker of water? Explain using the concept of the energy hill.
124) Explain how the analogy of a ball and a hill is useful for describing the forms of energy to beginning physiology students. Use the synthesis of glucose by plants and the break down of glucose by humans as specific examples of the energy hill.
125) What are the five ways that cells regulate flow of molecules through their metabolic pathways?
126) After coming off a ribosome, several things can happen to the newly synthesized protein. Name three.
127) Candy bars are well known to supply large amounts of energy for metabolism. With all this energy trapped inside, how can the candy bar sit still on the shelf in the grocery store?
128) A certain reaction pathway consists of four steps. How would decreasing the amount of enzyme that catalyzes the second step affect the process?
129) What is chemiosmotic theory? What is its role in metabolism?
130) Vitamins are precursors for Name two vitamins that are required for metabolic reactions.
131) Once the promoter region of a gene is activated, unwinds the DNA of the downstream gene and begins the process of What is the molecule generated by this process? How does the cell control the amount of this molecule released from the nucleus?
132) Once the mRNA for a particular gene has been transcribed, how is the mRNA that will be released from the nucleus processed?
133) How is the single-stranded mRNA that leaves the nucleus translated into proteins?
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
134) The folding of proteins occurs through the formation of weak and bonds between amino acids. Much stronger covalent bonds like bonds can occur between amino acids. 134)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
135) Some diseases, such as phenylketonuria, classical hemophilia, cystic fibrosis, and muscular dystrophy are a result of enzyme malfunction. Each of these diseases is inherited. Explain how there might be a relationship among these observations.
136) Explain how it is possible for an enzyme to catalyze a chemical reaction in two different directions.
137) Glucose-6-phosphate binds to the enzyme glycogen synthase, increasing the probability of enzyme-substrate binding. Glucose-6-phosphate is an example of a(n) . Based on its name, what do you think is the role of glycogen synthase?
138) For the following strand of DNA, use the table below to provide: bases for the complementary mRNA and bases for the corresponding tRNA molecules and the associated amino acids. What do you notice about the relationship between the DNA and the anticodons? What do you notice about the genetic code for proline in the peptide? How would the loss of the first G or switching that G to a T affect the structure and function of this protein?
DNA: GGC CTA CAA GCC GGA ACA GTT ACC GCG TAA CGA mRNA: tRNA: protein:
139) Create a map that integrates the following terms: alternative splicing, constitutive, interference, mRNA, post-translation modification, regulated, repression, induction, translation, and tRNA. Add terms as needed.
140) Draw a graph of the free energy of a molecule as a function of time for an exergonic reaction and endergonic reaction. Label on the graph "activation energy" and "net free energy change." How would these reactions be altered by the presence of an enzyme for this reaction?
141) Graph the effects of changing pH on enzyme activity. In humans, what is the pH for optimal activity of most enzymes?
142) Carbon dioxide and water readily combine to form carbonic acid. The change in pH as the acid dissociates can be demonstrated with an indicator dye that changes color at a particular pH. In your physiology lab, you perform this experiment in two beakers containing room-temperature water and indicator, labeled as A and B. CO2 is bubbled into solutions A and B from a pressurized tank for 10 seconds. A stopwatch was used to measure long it took for the solutions to change color. The data below were generated by the students.
Student Time for reaction (seconds):
Write the chemical equation for this reaction. Determine average values for each beaker. Explain how the reactio differed. What may be present in beaker B that is absent from beaker A?
143) Carbon dioxide and water readily combine to form carbonic acid. The change in pH as the acid dissociates can be demonstrated with an indicator dye that changes color at a particular pH. In your physiology lab, you perform this experiment in two beakers containing room-temperature water and indicator, labeled Resting and Exercise based upon the status of the student who exhaled through a straw into the solution. The Resting student had been sitting at the table for 30 minutes before exhaling while the Exercise student had just finished sprinting up the stairs to class late. A stopwatch was used to measure how long it took for the solutions to change color. The following data were generated by the students. Explain why the time required for the color to change was different between groups, using the word substrate in your answer.
144) Carbon dioxide and water readily combine to form carbonic acid. The change in pH as the acid dissociates can be demonstrated with an indicator dye that changes color at a particular pH. Following this lab in which the color of the solution was observed to change, one lab group forgot to dump the beakers at the end of the lab period. The next day would you expect the beakers to look the same as they did after being bubbled with CO2? If not, explain in terms of reversible reactions and equilibrium disturbance.
145) Bovine insulin is composed of 30 amino acids. What is the minimum number of DNA triplets in the insulin gene, based on the amino acid length? What is the minimum number of DNA bases in the coding region? Explain how and why the actual number of triplets in the gene may differ.
146) Analysis of a single DNA strand yielded this information on amounts of some nucleotides: 43 units of cytosine and 51 units of adenine. What amounts would you expect of guanine and thymine in that strand? What amounts would you expect of all bases in the complementary strand?
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
147) Maryam eats an apple and starts thinking about how the enzymes in her mouth are breaking the large structure of the apple down into smaller, more simple structures. This is an example of
A) anabolism.
C) metabolism.
B) catabolism.
D) None of the above.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
148) Your friend is learning about cellular metabolism. You want to help her learn this material so you decide to write out, on poster board, the metabolism of glucose. To make sure your friend really understands the material, you represent the cellular metabolism pathways; one using words, and one using chemical formulas. Draw out what your poster board would look like.
Answer Key
Testname: UNTITLED23
1) C
2) D
3) A
4) D
5) A
6) D
7) C
8) D
9) B
10) B
11) A
12) A
13) B
14) D 15) C
16) A
17) B
18) C
19) D
20) A
21) B
22) A
23) C
24) B
25) A
26) C
27) D
28) A
29) D
30) A
31) B
32) B
33) C
34) E
35) C
36) E
37) C
38) C
39) C
40) A
41) B
42) B
43) B
44) D
45) C
46) A
47) D
48) B
49) E
50) A
Answer Key
Testname: UNTITLED23
51) B
52) D
53) E
54) E
55) C
56) A
57) A
58) B
59) C
60) A
61) C
62) reversible
63) endergonic
64) exergonic
65) covalent
66) enzymes
67) key intermediate
68) Reaction rate
69) oxygen
70) glucose-6-phosphate, ATP
71) ATP to ADP
72) phosphorylation
73) NADH, mitochondria
74) potential energy, intermembrane space
75) inner mitochondrial membrane, cytochromes
76) anticodon
77) transcription, nucleus, translation
78) tRNA
79) RNA polymerase, magnesium or manganese
80) mRNA
81) rRNA
82) single
83) RNA interference
84) constitutively active
85) promoter, induce
86) exon
87) exon
88) dehydration synthesis
89) molecular chaperones
90) Potential energy is the energy an object has stored in its position, while kinetic energy is energy associated with a moving object/movement.
91) When a reaction is at equilibrium, the ratio of the substrates to the products is always the same because reaction rate is constant.
92) ATP easily acquires the energy stored in complex biomolecules such as carbohydrates and its phosphate bonds are readily broken to release energy.
93) Oxidation-reduction reactions transfer electrons or protons between substrates. Hydrolysis-dehydration reactions form or break a chemical bond between organic substrates by removing or adding a water molecule. Transfer reactions (addition-subtraction-exchange reactions) add, remove, or exchange a functional group (phosphate or amino groups) among the substrates. Ligation reactions join molecules using the energy from an ATP molecule.
94) C
Answer
95) D 96) C
97) A
98) C
99) A
100) D
101) C
102) C
103) C
104) B
105) B
106) D
107) C
108) D
109) D
110) A
111) B
112) A
113) E
114) D
115) DNA, the promoter, where to bind to the DNA
116) Oxidation-reduction reactions occur when electrons are transferred from one molecule to another. The molecule that is oxidized in the reaction loses electrons while the reduced molecule gains electrons. OIL RIG (oxidation is loss, reduction is gain) is the mnemonic provided in the textbook.
117) Only B is correct as written. A could be corrected by clarifying that it is concentration or amount of substrate that ceases to change; individual molecules can form or break at any given time, but the overall amount will not change because synthesis will be balanced by degradation. C is incorrect because the reactions continue as long as conditions such as presence of catalysts, favorable temperature, and presence of substrates are maintained. As a given enzyme can both synthesize and degrade, both processes will continue even at equilibrium. D is incorrect because at equilibrium there is no net change in amounts, but it is not necessary for concentrations of substrates and products to be the same as each other.
118) B and C are correct as written, but B requires some clarification. A is incorrect because enzyme molecules are not consumed in chemical reactions and will continue to be active until acted upon by environmental conditions (temperature, pH, or modifiers). B is correct only when the product is removed from the system. If the product remains, the enzyme will reach equilibrium where the ratio of substrate to product is constant (Correct Answer C). In D, if the product of the reaction is removed, the reaction would continue to proceed to form new product (assuming enzymes and substrates are available). Chemical reactions continue if conditions are favorable, including presence of substrate and enzyme and fairly constant temperature and pH. In living systems, most chemical reactions do not have a steady supply of substrate; for example, the chemical reactions of digestion will stop when the small intestine is empty.
119) A. False. There may be more than one enzyme for the reactions listed, but a given enzyme is often capable of performin reaction in both directions.
B. False. The enzyme for both reactions could be the same, but often a particular enzyme is more likely to perform the f reaction while a different enzyme is more likely to perform the reverse.
C. False. If the reactions are at equilibrium, both are occurring at the same time. If they are not at equilibrium, it is possi the reaction is occurring only in one direction. In addition, cells can have different enzymes for each reaction direction t be differentially controlled (i.e., one active and the other inactive).
D. True. By definition, a reaction is at equilibrium when both directions are occurring such that there is no net change in amounts of substrates and products.
E. False. Equilibrium is not necessarily established, especially in a cell where a product is immediately removed from th for use elsewhere, such as the product ATP, or if a given enzyme does not perform the reverse reaction.
F. True. Any change in amounts of enzyme, substrate, or product will disturb equilibrium, and if these things constantl equilibrium cannot be established.
G. False. Equilibrium can be disturbed by changing the amount of enzyme, substrate, or product, or by altering the enz efficacy by changing temperature or pH.
120) Many enzymes are normally present in the blood in a particular range of concentrations. Alterations in these concentrations can be associated with abnormal conditions. For example, elevation in the digestive enzyme amylase, produced by the pancreas, may indicate pancreatic disease. Elevation of enzymes that normally operate inside cells can indicate tissue damage, such as the elevation of creatine kinase following myocardial infarction. Low amounts of hexosamidase A can indicate Tay-Sachs disease. In the examples given, the amylase and hexosamidase enzyme changes are direct results of the disease, whereas enzymes elevated because of tissue damage are the result of cellular damage and not a direct change in the enzyme itself.
121) Only A is irreversible in animal systems. The products are rapidly removed from the system as soon as they are formed, so they are not recombined. This reaction is reversible in plants, which form and store glucose for food, but also need to use some of the glucose to make ATP.
122) A concentration gradient is a difference in concentration of a particular molecule between the cytosol of a cell and the interstitial fluid. A concentration gradient represents potential energy because of the tendency of molecules to diffuse from areas of high to areas of low concentration.
123) In the presence of the enzyme, the reaction will occur much more rapidly thereby forming the carbonic acid faster. When the enzyme is present, the hill the ball must roll up before it can continue down the hill is lower than in the absence of the enzyme.
124) Energy is required for a person to move a ball from a lower height to a higher one, and that the ball will automatically roll down the hill if allowed to, without further input of energy. The substrates CO2 and H2O require energy to be combined into C6H12O6; the energy of the sun provides this energy to "roll" the substrates up the energy hill as they combine. The glucose then contains the potential energy provided by the sun. When enzymes are present, the molecule easily breaks down to CO2 and H2O releasing energy that is used by the cell to perform work.
125) 1. by controlling the enzyme concentration
2. by producing modulators (allosteric and covalent)
3. by using two different enzymes to catalyze reversible reaction
4. by isolating enzymes within intracellular organelles (compartments)
5. by maintaining an optimum ratio of ATP to ADP
126) The possible answers include the post-translational modifications:
1. folded into three-dimensional shapes
2. cross-linkages (disulfide bonds) between different regions of its amino acid chain
3. be cleaved into fragments
4. attach other molecules or groups (e.g., methylation)
5. assemble with other peptides (subunits) into polymeric proteins
127) Candy bars contain large amounts of energy, but it is trapped as potential energy in carbohydrates (both simple and complex). The carbohydrates must be broken down and enter the cell's metabolic pathways in order to convert the potential energy to another form.
128) Decreasing the amount of enzyme at the second step would slow down the whole series of reactions because less product would be available as substrate for the next two steps. The net result would be a decrease in the rate of production of the product and therefore, within a specified time, a decrease in the amount of the product.
129) Chemiosmotic theory is a model that explains the movement of electrons through the electron transport system. This occurs across the mitochondrial inner membrane and drives oxidative phosphorylation and production of ATP by ATP synthase.
130) coenzymes
Vitamins required for metabolic reactions include the B vitamins such as folic acid, biotin, and pantothenic acid and vit
131) RNA polymerase, transcription
The RNA polymerase transcribes a single-stranded mRNA. The cell can decrease mRNA by controlling the activity of t promoter with transcription factors if the gene is not constitutively expressed. Decreases in an inducer or increases in a repressor would reduce the amount of mRNA available for release. In addition, the amount of mRNA released is also affected by the availability of interfering RNA (siRNA or miRNA). Increases in interfering RNA that can inactivate or destroy mRNA would reduce the amount of mRNA released from the nucleus.
132) The mRNA that is initially transcribed contains regions that are not part of the protein that will be translated. These noncoding regions of mRNA (introns) are removed from the mRNA by splicing. The mRNA then only contains the coding sequences (exons) that can be released from the nucleus to be translated by the ribosome. Due to alternative splicing, the structure of the protein can be different which leads to isoforms of a protein.
133) Ribosomes have two subunits (large and small) that are composed of proteins and rRNA. The small subunits bind to the mRNA followed by the large subunit which sandwiches the mRNA. The tRNA (contains the anticodon and associated amino acid) binds to the complementary mRNA. A second tRNA arrives for the next codon and, via dehydration synthesis, a peptide bond is formed between amino acids, which releases the first tRNA from the mRNA and allows the next tRNA to bind. This process continues until the stop codon is reached.
134) hydrogen, ionic, disulfide, cysteine
135) Inheritance is determined by the message coded into DNA; a mutation relays a faulty message, which disrupts protein synthesis, resulting in either a faulty protein or complete absence of the protein. Enzymes are proteins. When the instructions for the synthesis of their structure are changed, they may not be able to perform their function, producing a disease condition. If the disease is not fatal prior to puberty and does not render its victim unable to reproduce, the faulty DNA will be copied during gametogenesis and will appear in a predictable percentage of offspring.
136) Both the substrate and product have a 3-D shape complementary to the active site of the enzyme. In a synthesis reaction between two organic monomers, the enzyme holds the substrates in a position that greatly increases the likelihood of bond formation between them, and as the bond forms to produce a dimer, the affinity of the enzyme for the substrates increases. The dimer is also complementary to the active site of the enzyme, and if a dimer molecule happens to bind to the enzyme, becoming the substrate, the bond between the monomers becomes strained as the intermediate is formed and can break. If this happens, the reaction is a degradation and the products are the monomers. The tightest binding is between the enzyme and the intermediate form, different in structure compared to either the substrates or the product. Thus, it is equally likely that the reaction will be a synthesis or a degradation, if no other factors are considered.
137) (allosteric) modulator of glycogen synthase
Glycogen synthease is required for the synthesis of glycogen.
138) mRNA: CCG GAU GUU CGG CCU UGU CAA UGG CGC AUU GCU
tRNA: GGC CUA CAA GCC GGA ACA GUU ACC GCG UAA CGA
protein: pro asp val arg pro cys gln trp arg ile ala
The DNA triplets and the tRNA anticodons are identical except that U (in tRN.A substitutes for T (in DNA). In this peptide, proline was specified by two different codons, CCG and CCU.
1 base lost: arg met phe gly leu val asn gly ala leu
1 base altered: thr asp val arg pro cys gln trp arg ile ala
Loss of a base results in dramatic changes in the protein structure (1 less amino acid and a start codon at the second cod which means the proteins are unlikely to be functional. However, a single base substitution would have a single amino different, which make the proteins more likely to be functional although the function may still be altered.
139) See Figure 4.18 through 4.21 in the chapter.
140) See Figure 4.3 in the chapter. The activation energy would be reduced which would increase the rate of these reactions.
141) See Figure 4.6 in the chapter. The optimal pH for most enzymes is 7.4.
142) CO2 + H2O → H2CO3 → H+ + HCO3-
Average time for beaker A to change is 59 seconds, and for beaker B to change is 2 seconds, that is, the reaction occurred in solution B. For this to occur, an enzyme such as carbonic anhydrase must have been present in beaker B.
143) With each breath, CO2 is present in the exhaled air. The students who exercised exhibited an elevated rate of CO2 generation by the metabolic cycle. Thus, the substrate concentration was higher for the Exercising student than the Resting student, which is why the time for the solution to change color was less.
144) The next day, the solutions had changed back to their original color (before being bubbled with CO2). The carbon dioxide dissipated over night, driving the reaction back in the reverse direction, because the amount of substrate changed. This caused the pH to increase again, above the level required to maintain the color change.
145) Ignoring stop and start codons, RNA splicing, and post-translational modification, a peptide of 30 amino acids is specified by 30 triplets. As a triplet is 3 bases in length, this means a minimum of 90 DNA bases (30 triplets × 3 bases per triplet) is present in the insulin gene. The actual number of triplets and bases is higher, because the gene starts and ends with start and stop sequences, some of the mRNA codons are excised prior to translation and peptide sequence, and furthermore post-translational modification of the peptide may remove additional amino acids. Thus, the number of amino acids in the peptide is related to gene length but doesn't allow precise calculation of gene length.
146) There is no way to determine the amounts of guanine and thymine in the analyzed strand based on the amounts of cytosine and adenine; the guanine and thymine would have to be determined directly. In the other strand, the amount of guanine equals the amount of cytosine in the analyzed strand, and the amount of thymine equals the amount of adenine in the analyzed strand, because of the way the bases pair to hold the strands together. Once the amounts of guanine and thymine in the first strand are determined, the amounts of cytosine and adenine can be determined in the complementary strand.
147) B
148) Glucose + oxygen water, carbon dioxide, energy, and heat
C6H1206 + O2 H2O + CO2 + ATP + heat
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Which body fluid compartment contains high levels of K+ , large anions, and proteins?
A) intracellular fluid
B) interstitial fluid
C) plasma
D) A and C
E) A and B
2) Which body fluid compartment contains higher levels of Na+ , Cl, and HCO3-?
A) plasma
B) intracellular fluid
C) interstitial fluid
D) both plasma and intracellular fluid
E) both plasma and interstitial fluid
3) Which is NOT a type of mediated transport?
A) secondary active transport
C) facilitated diffusion
B) simple diffusion
D) primary active transport
4) Bulk flow is fluid flow as a result of a(n) gradient.
A) concentration
B) pressure
C) electrical
D) Two of the answers are correct.
E) None of the answers are correct.
5) Water is a polar molecule, yet can move through the nonpolar portions of cell membranes. Which transport process is responsible?
A) simple diffusion
B) symport
C) facilitated diffusion
D) uniport
E) antiport
6) Permeability is a property of
A) ions.
B) proteins.
C) membranes.
D) solutes.
E) solvents.
7) The term cellular (metabolic) energy indicates any biological process requiring
A) ATP.
B) thermal energy.
C) energy in any form.
D) chemical energy.
E) thermal energy and chemical energy.
8) What are the two extracellular fluid compartments in the body?
A) interstitial fluid and intracellular fluid
B) intracellular fluid and plasma
C) plasma and the fluid portion of the blood
D) plasma and interstitial fluid
E) None of the answers are correct.
9) Saturation occurs when
A) molecules are moved by the use of vesicles.
B) a preference of a carrier protein for a substance is demonstrated based on the differing affinities of the carrier for the substrates.
C) the energy required to move molecules results from a high-energy bond.
D) a group of carrier proteins is operating at its maximum rate.
E) a carrier molecule has the ability to transport only one molecule or a group of closely related molecules.
10) A cell transports large molecules out of the cell by
A) active transport.
B) endocytosis.
C) phagocytosis.
D) diffusion.
E) exocytosis.
11) Which is a way for solutes to move from an area of high solute concentration to an area of low solute concentration?
A) facilitated diffusion
B) active transport
C) osmosis
D) A and B
E) None of the answers are correct.
12) In an epithelium, the apical membrane is also known as the membrane.
A) basement
B) nictitating
C) serosal
D) mucosal
E) basolateral
13) Hyposmotic solutions have
A) lower concentrations of solutes than other hyposmotic solutions.
B) higher concentrations of solutes than hyperosmotic solutions.
C) the same concentration of solutes as hyperosmotic solutions.
D) lower concentrations of solutes than hyperosmotic solutions.
E) None of the answers are correct. 13)
14) Which statement about the Na+/K+ pump is FALSE?
A) It transports Na+ and K+ in a 1:1 ratio.
B) Its activity requires energy input.
C) It transports Na+ out of the cell and K+ into the cell.
D) It is present in neurons.
15) Which statement about the resting membrane potential is TRUE?
A) It is due in part to the presence of extracellular proteins.
B) The inside of the membrane is positively charged compared to the outside.
C) It is normally equal to zero volts.
D) It results, in part, from the concentration gradients for Na+ and K+
16) Voltage-gated channels and antiport carriers are both types of
A) structural proteins.
C) enzymes.
B) transporters.
D) receptors.
17) The resting membrane potential in most cells is approximately
A) -70 mV. B) 0 mV. C) -35 mV. D) +70
18) Compared to the outside surface, the inside of a resting cell membrane is
A) positively charged whenever the sodium-potassium pump is active.
B) negatively charged.
C) positively charged.
D) continuously reversing its electrical charge.
E) electrically neutral.
19) Caveolae and clathrin-coated pits are both used in
A) phagocytosis.
B) endocytosis.
C) exocytosis.
D) All of the answers are correct.
E) None of the answers are correct.
20) As the charge on the membrane of a cell approaches 0 from -70 mV, the cell is
A) hyperpolarizing.
B) becoming more difficult to stimulate.
C) depolarizing.
D) repolarizing.
E) B and D.
21) Which is NOT involved in creating the resting potential of a cell?
A) resting membrane permeability for potassium ions greater than sodium ions
B) diffusion of sodium ions into the cell
C) resting membrane permeability for sodium ions greater than potassium ions
D) diffusion of potassium ions out of the cell
22) Passive transport refers to a process that requires no
A) pressure gradient.
B) concentration gradient.
C) energy at all.
D) electrical gradient.
E) input of energy.
23) Which is NOT true about diffusion in the human body?
A) Net movement of molecules occurs until the concentration is equal.
B) Smaller molecules take longer to diffuse than larger ones.
C) Diffusion is rapid over short distances and slower over longer distances.
D) Diffusion occurs faster at higher temperatures.
24) Gated channels for sodium ions may include
A) chemical gates, which respond to ligands.
B) mechanical gates, which respond to pressure.
C) voltage gates, which respond to electrical signals.
D) All of the answers are correct.
E) None of the answers are correct.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the membrane protein with its function.
25) structural proteins
26) enzymes
27) receptors
28) transporters
Match the transport process to its description.
29) the movement of substances from an area of high concentration to an area of low concentration
30) the movement of substances through proteins embedded in the cell membrane; requires an input of energy
31) the movement of substances against the concentration gradient
32) tends to create an equilibrium state
A) bind ligands as part of chemical signaling
B) moves substances across membranes
C) catalyze chemical reactions D) form cell junctions
passive transport
B) active transport
Match the transport process to its description.
33) the substances of molecules from an area of high concentration to an area of low concentration
34) the use of ATP to move molecules
35) a form of mediated transport
36) exhibits specificity, competition, and saturation
Match the type of transport with its description.
37) between adjacent cells
38) from an organ's lumen to the extracellular fluid
39) in one side of a cell and out the other
40) movement from the extracellular fluid into the lumen of an organ
A) facilitated diffusion B) both C) neither
A) transcellular transport
B) secretion
C) paracellular transport D) absorption
Match the terms to changes presented, assuming a resting membrane potential of -70 mV. Answers may be used once, more than once, or not at all.
41) to -50 mV from resting potential
42) to -70 mV from -50 mV
43) to -90 mV from resting potential
44) to +30 mV from resting potential
45) to -70 mV from -90 mV
46) any mV value, regardless of relationship to resting potential
A) repolarization
B) depolarization
C) hyperpolarization
D) electrical polarization
Match the potential or potential change with its cause. Assume ion movements are net movements. Answers may be used more than once all.
47) Na+ enters the cell
A) depolarization
48) K+ leaves the cell, bringing its potential back to the resting value
49) Cl- enters the cell
50) membrane potential is 0 mV
A) depolarization
B) repolarization
C) hyperpolarization
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
51) This type of membrane protein extends all the way through the cell membrane into both the extra- and intracellular fluids: . 51)
52) The membrane proteins that catalyze reactions that take place on the external or internal surface of the cell are . 52)
53) The membrane proteins that bind to a ligand and act in the body's chemical signaling system are . 53)
54) The membrane proteins that maintain the shape of the cell membrane, form cell junctions, and allow cells to attach to the extracellular matrix are . 54)
55) The membrane proteins that bind with specific substrates and change shape to transport them across the cell membrane are . 55)
56) Carrier proteins operating at their maximum rate are said to be . 56)
57) The three types of gated channels are , , and . 57)
58) Membrane protein pores that can be opened and closed are called channels. 58)
59) The Na+-K+-ATPase pumps (this number of) Na+ ions (into/out of) the cell and (this number of) K+ ions (into/out of) the cell. 59)
60) A pump that helps maintain an electrical gradient, such as the Na+-K+-ATPase is a(n) pump. 60)
61) Channel proteins that allow water to pass are called 61)
62) Membrane protein pores that are essentially always open are called or channels. 62)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
63) Which is a unique characteristic of glucose as a solute in biological systems?
A) It enters the interstitial fluid before going into the cell.
B) It is converted into dextrose inside the cell.
C) It is freely penetrating and can pass in and out of the cells at any time.
D) 100% of it is absorbed into the cell from the extracellular fluid. 63)
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
64) The two extracellular compartments in the body are and . 64)
65) The walls of the separate the two extracellular fluid compartments. 65)
66) The ability of a carrier molecule to transport only one specific molecule or a group of closely related molecules is called 66)
67) At rest, cells have an unequal distribution of ions on either side of the cell membrane, producing the 67)
68) At rest, most cells have a voltage of mV. 68)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
69) A cell membrane that is selectively permeable
A) is impermeable to all substances but water.
B) will only allow substances in or out if their concentration in the cell is above or below a certain point.
C) can change which substances pass through by changing its lipid and protein content.
D) randomly chooses which substances will pass through. 69)
70) Fick's law of diffusion states that the rate of diffusion across a membrane is proportional to
A) membrane permeability, but inversely proportional to concentration gradient and surface area.
B) membrane thickness and surface area.
C) surface area and membrane thickness, but inversely proportional to concentration gradient.
D) concentration gradient, surface area, and membrane permeability.
71) Which would increase the rate of diffusion across a cell membrane?
A) a decrease in membrane permeability
B) a decrease in the concentration gradient
C) a decrease in membrane thickness
70)
D) a decrease in the surface area of the membrane 71)
72) Pinocytosis is a type of
A) exocytosis.
B) phagocytosis.
C) exocytosis and phagocytosis.
D) endocytosis and exocytosis.
E) endocytosis.
73) Sodium ions are more concentrated in the extracellular fluid than in the intracellular fluid. This is an example of
A) electrical disequilibrium.
C) osmotic equilibrium.
72)
73)
B) chemical disequilibrium.
D) failed homeostasis.
74) The inside of a resting cell is slightly negative relative to the outside. This is an example of
A) failed homeostasis.
C) electrical disequilibrium.
B) chemical disequilibrium.
D) osmotic equilibrium.
75) Which property of diffusion best explains why a circulatory system is needed in multicellular organisms?
A) Diffusion is rapid over short distances but much slower over long distances.
B) Diffusion rate is inversely related to molecule size.
C) Molecules move from an area of higher concentration to an area of lower concentration.
D) Diffusion can take place in an open system or across a partition that separates two systems.
76) Facilitated diffusion and active transport differ in that
A) potential energy is required for active transport but not for facilitated diffusion.
B) ATP is necessary for active transport, but not for facilitated diffusion.
C) facilitated diffusion moves water across the cell membrane, whereas active transport does not.
D) facilitated diffusion uses a substrate to bind to a protein carrier, whereas active transport does not.
E) facilitated diffusion uses cell membrane proteins to move substances, whereas active transport does not.
77) Water will always move from areas to areas, if the membrane is permeable to water.
A) hypotonic, hypertonic
C) hypertonic, isotonic
B) hypertonic, hypotonic
D) isotonic, hypotonic
78) Substances that readily dissolve in water and do not readily dissolve in lipids are
A) hydrophilic and lipophobic.
C) hydrophobic and lipophilic.
B) hydrophobic and lipophobic.
D) hydrophilic and lipophilic. 78)
79) Which molecules can move across the phospholipid bilayer by simple diffusion?
A) steroids
B) water
C) lipids
D) lipids and water
E) All of the answers are correct.
80) A cell that is permeable to Solute X is placed into solution containing a higher concentration of X. Diffusion occurs until equilibrium is reached. At this time,
A) there is no further movement of Solute X across the membrane.
B) there is no further change in concentration of Solute X.
C) Both of the statements are correct.
D) Neither of the statements is correct.
81) Cations will each other.
A) attract B) repel C) not react with
82) Anions will each other.
80)
A) attract B) repel C) not react with 82)
83) The cell membrane acts as a good
A) electrical gradient. B) source of ions. C) electrical conductor. D) electrical insulator.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
84) Describe the distribution of water in the body's fluid compartments.
85) Explain why transporting epithelial cells are said to be polarized. Explain why a membrane potential is said to be polarized.
86) Explain the term resting membrane potential difference.
87) Describe the validity of this statement: "The extracellular and intracellular fluid compartments are in equilibrium."
88) Explain how the body can be in a state of osmotic equilibrium and chemical disequilibrium.
89) Explain why the composition of the phospholipid bilayer determines how easily water passes through it.
90) How do most polar molecules move through a cell membrane? Explain why water, a polar molecule, is able to cross the nonpolar portion of a cell membrane.
91) Water can cross a cell membrane by a variety of means. List at least three. Do water molecules cross a membrane through the same molecules as other solutes? Explain. Are all cells equally permeable to water? Explain.
92) Explain the differences between channel proteins and carrier proteins and why cells need both.
93) Briefly explain the difference between open channels and gated channels.
94) Explain the difference between Fick's law of diffusion and the flux of a molecule.
95) Name two ways the selectivity of a channel is determined.
96) Compare and contrast facilitated diffusion and active transport.
97) Distinguish between these statements, explaining what is correct or incorrect about each, and what requires clari Relate your answers to the energy hill concept from the previous chapter.
A. Passive transport requires energy.
B. Active transport requires energy.
C. Vesicular transport requires energy.
98) Distinguish between the following terms: cotransport; antiport; symport.
99) Compare and contrast primary active transport and secondary active transport, noting any special differences.
100) Explain the process of secondary active transport and how it uses ATP.
101) Explain the purpose of having both the reversible GLUT transporters as well as the SGLT transporters in the body.
102) Compare and contrast penetrating solutes and nonpenetrating solutes.
103) Explain the term dynamic steady state.
104) Describe the three major roles of structural proteins.
105) Draw a membrane channel protein from two different perspectives, clearly indicating the pore in each.
106) How is a carrier protein like a ship canal?
107) What property of some cell membranes is associated with impermeability to water molecules?
108) Explain the processes of receptor-mediated endocytosis and exocytosis.
109) Explain in your own words the five general properties for diffusion and the two general properties for simple diffusion across a membrane.
110) Write the five rules for osmolarity and tonicity. Are the relative osmolarity and tonicity of an extracellular solution compared to intracellular fluid always the same? If they are, explain why. If they are not, give specific examples of when they are different.
111) Explain the following:
A. chemical reaction equilibrium
B. chemical equilibrium
C. osmotic equilibrium
112) You are a server in a restaurant, always interested in going the extra mile for your customers. Patrick, a regular customer in your section, has ordered sweet iced tea and has an appointment in 10 minutes, so he must drink quickly then leave. The kitchen staff makes only unsweetened tea, but there are sugar packets on the tables. What should you do for Patrick to provide the best sweet tea, and what general principle of diffusion does this illustrate? (Hint: Will sugar dissolve quickly in an iced drink?)
113) Provide the basic physics definition of the term fluid. What is bulk flow relative to body compartments? What types of matter move by bulk flow? What is fundamentally different in the behavior of these types of matter?
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
114) When you eat a large meal and your body absorbs a lot of glucose and that makes its way to the interstitial fluid before going into the cell. 100% of the glucose should be absorbed into the cell from the interstitial fluid. Why does nearly all of the glucose enter the cell, rather than only half of it?
A) The cells make ATP so fast, they use up all the glucose as soon as it enters the cell.
B) Insulin forces glucose into the cell against a concentration gradient.
C) It is modified by the cell, so there is still more glucose on the outside of the cell than inside it.
D) It is moved by active transport. 114)
115) If a 10% sucrose solution is separated from a 20% sucrose solution by a membrane impermeable to sucrose, in which direction will net movement of water occur?
A) from the 20% sucrose solution to the 10% sucrose solution
B) from the 10% sucrose solution to the 20% sucrose solution
C) A and B
D) There will be no net movement of water in this case.
E) None of the answers are correct.
116) If a 10% sucrose solution is separated from a 20% sucrose solution by a membrane permeable to sucrose, in which direction will net diffusion of sucrose take place?
A) from the 10% sucrose solution to the 20% sucrose solution
B) from the 20% sucrose solution to the 10% sucrose solution
C) A and B
D) neither A or B
E) There will be no diffusion in this case.
117) The concentration of calcium inside a cell is 0.3%. The concentration of calcium outside the cell is 0.1%. How could the cell transport even more calcium to the inside?
A) passive transport
B) osmosis
C) exocytosis
D) active transport
E) All of the answers are correct.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
118) When the ions move across the cell membrane, an electrical potential change results. As you are probably aware, nerves stimulate skeletal muscle movement. When you place your finger on a sharp object (such as a tack), you quickly draw your hand away and develop a sensation of pain. Which types of channels are operating under these conditions to allow nerve conduction and subsequent muscle movement?
119) Design an experiment to test whether molecular weight influences the rate of diffusion. List all controlled variables.
120) Cells of the intestine are very permeable to water while some cells of the kidney tubule are not at all permeable to water. Can you suggest some ways these two types of cells might be different from each other?
121) How are molarity and osmolarity different? What property of salts necessitates this distinction? How does this property affect the behavior of water?
122) Define osmolarity and tonicity. How are they similar? How are they different?
123) Explain the steps that occur in a pancreatic beta cell so that insulin is secreted.
124) Indicate the relative osmolarities of the following solutions.
Solution a: 2 osmolar NaCl
Solution b: 1 molar NaCl
Solution c: 900 milliosmolar glucose
A. a is osmotic to b. D. a is osmotic to c.
B. b is osmotic to a. E. b is osmotic to c.
C. c is osmotic to a. F. c is osmotic to b.
125) When the kidney goes into failure, one of the signs that doctors will see is that red blood cells will shrink. Why does this happen in kidney failure? What process is occurring to the blood cells?
126) Red blood cells with an internal osmolarity of 300 mOsM are placed in the following solutions. Designate each s according to its osmolarity and tonicity, and explain what happens to the cells and why.
A. 200 mOsM NaCl
B. 400 mOsM urea
C. 100 mOsM urea plus 200 mOsM NaCl
D. 300 mOsM urea
E. 300 mOsM NaCl
F. 200 mOsM urea plus 300 mOsM NaCl
G. 400 mOsM NaCl
127) There are two solutions separated by a semipermeable membrane. Solution A is 0.3 M glucose, and solution B is 0.15 M NaCl. Will there be a net flow of water across this membrane? Why or why not?
128) There are two solutions separated by a semipermeable membrane. Solution A is 0.2 M NaCl and solution B is 0.1 M CaCl2 Will there be a net flow of water across the membrane? Why or why not?
129) Define the term transport maximum, and describe a way cells can increase their transport capacity.
130) Diuretics cause the kidneys to produce large amounts of urine. Unfortunately, they can also cause the loss of large quantities of K+ in the urine. What effect might prolonged use of diuretics have on nerve or muscle cells?
131) If someone has a muscle cramp or spasm, a commonly discussed treatment is to consume a banana (or another food high in potassium). Why would this be a possible treatment for muscle cramps or spasms?
132) Which membrane transport process(es) is/are abnormal in people with cystic fibrosis? What is the consequence of the abnormal transport? Which organ systems are affected? How is this disease treated? How long do cystic fibrosis patients normally live? What are some of the possible causes of death related to this disease? What is the cause of cystic fibrosis?
You are walking to school one day when you notice an alien spaceship that has crashed in a nearby field. You and some other physiology students collect samples from the aliens inside of the spaceship. First, you collect a liquid sample of what appears to be alien blood so that you can test for the concentration of solutes inside the alien blood cells. You then extract some of these cells, place them in various concentrations of glucose in water, then look at them under the microscope. Below is what h to the cells when they are placed in various concentrations of glucose:
Percent Glucose in Water Condition of Alien Blood Cells
0.02% cells lyse
0.05% cells lyse
0.10% cells lyse
0.12% cells shrink
0.20% cells shrink
133) Refer to Table 5.1. From cells located in another part of the alien's body, you find that the protein-to-lipid ratio of the cell membrane is about 20% protein, 78% lipid, and 2% carbohydrate. Assuming the aliens use their cells as Earthlings do, and have the same terrestrial physiology, what is the most likely function of these cells?
134) Refer to Table 5.1. How can you determine the osmolarity and tonicity of the alien blood and alien cells?
135) How does the beta cell in the pancreas react to release insulin when glucose levels are low?
136) What is the approximate concentration of solute present in alien blood cells?
137) A patient is given an intravenous infusion of glucose solution that has a concentration of 25 grams of glucose per liter. If the infusion is given at a rate of 4 milliliters per minute, what is the mass flow of glucose into the body?
138) A 70-year-old man weighs 145 pounds and has 48% of his body weight in the form of water. How many liters of water is that?
139) A dehydrated patient needs a saline solution IV in order to be rehydrated. Unfortunately the hospital is poorly stocked with saline solutions. The nurse was asked by the doctor to mix up 1 L of a 0.45% saline solution using NaCl and distilled water. How would she do this? What is the osmolarity of this solution?
140) Based on what you know about the characteristics of membrane transport, explain the results shown on the grap mixture consists of equal parts of glucose and fructose at the indicated concentration.
141) You mix one liter of 300 mOsM NaCl with two liters 450 mOsM glucose.
A. What is the osmolarity of the new solution?
B. What is the final osmolarity of the NaCl in the new solution?
C. What is the final osmolarity of glucose in the new solution?
D. What is the tonicity of this new solution compared to a red blood cell with 300 mOsM nonpenetrating solute?
142) Nurse Cameron has been asked to mix an isotonic intravenous solution for an emergency room patient who has lost a lot of blood. The available solutes include glucose (m.w. 180), NaCl (m.w. 58.5), and urea (m.w. 60). How should she make up 10 L of IV solution with an osmolarity of 290 mOsm (isosmotic), making sure that it will also be isotonic?
Answer Key
Testname: UNTITLED24
1) A
2) E
3) B
4) B
5) A
6) C
7) A
8) D
9) D
10) E
11) A
12) D
13) D
14) A 15) D
16) B
17) A
18) B
19) B
20) C
21) C
22) E
23) B
24) D
25) D
26) C
27) A
28) B
29) A
30) B
31) B
32) A
33) B
34) C
35) A
36) A
37) C
38) D
39) A
40) B
41) B
42) A
43) C
44) B
45) A
46) D
47) A
48) B
49) C
50) A
Answer Key
Testname: UNTITLED24
51) membrane-spanning
52) enzymes
53) receptors
54) structural proteins
55) carrier proteins
56) saturated
57) chemically gated channels, voltage-gated channels, mechanically gated channels
58) gated
59) 3 Na+ , out of, 2 K+ , into
60) electrogenic
61) aquaporins
62) open, leak (either order)
63) D
64) plasma, interstitial fluid
65) circulatory system
66) specificity
67) resting membrane potential
68) -70 (Note to instructor: All nerve cells are different, so you may wish to accept a range of similar values instead of insisting on precisely this value.)
69) C
70) D
71) C
72) E
73) B
74) C
75) A
76) B
77) A
78) A
79) E
80) B
81) B
82) B
83) D
84) 67% is intracellular.
33% is extracellular; of that 75% is in the interstitial fluid and 25% is in the plasma.
85) Transport epithelia have cells that are polarized with respect to distribution of transport proteins in the apical and basolateral membranes, i.e., different types of transporters in the two membranes. Cells are electrically polarized, meaning that the inside of the membrane is charged relative to the outside.
86) See "The Resting Membrane Potential" section of the chapter.
87) This statement is only partially true. The two compartments are in osmotic equilibrium, but they are not in chemical or electrical equilibrium. We use the term dynamic steady state to describe this relationship.
88) Osmotic equilibrium occurs because water moves freely between most cells and the extracellular fluid. Water will continue to move across membranes into more highly concentrated compartments until the concentrations (solute/volume) are equal, hence osmotic equilibrium. Osmotic equilibrium does not take into account what particles are present in each compartment, just the total number. The key is that water moves freely, but the solutes do not. Na+ and Cl- are more highly concentrated in the ECF while K+ and many anions are more highly concentrated inside the cell. Each ion is in chemical disequilibrium because it is not evenly distributed between the two compartments. Although the compartments are chemically different (chemical disequilibrium), when all solutes in one compartment are compared to all the solutes in another compartment they have the same total concentrations of solutes (are in osmotic equilibrium).
89) The phospholipid bilayer is a fluid mosaic and, depending on the function of the cell, contains various ratios of phospholipids, cholesterol, and proteins. Water molecules slip between the spaces between the fatty acid tails. Membranes with higher levels of cholesterol are less permeable to water because cholesterol fills these spaces.
90) Most polar molecules must be assisted by a protein, because the molecule will not interact with the nonpolar phospholipid tails. Examples are facilitated diffusion and active transport. Because water is very small and electrically neutral, it is able to diffuse between the phospholipid tails.
91) Water can cross through the phospholipid molecules, through special water channels called aquaporins, and through open or leak channels (pores) that also transport ions. Water can move through pores as a solvation shell around ions or independent of ions, because the watery interstitial fluid is continuous with the watery cytosol when pores are open. Some cells are more permeable to water, especially those with less cholesterol in the membranes and those with a high density of pores.
92) Channel proteins allow more rapid transport, but are not as selective. Carrier proteins are slower because of the shape change. They are also more selective and can move larger molecules than channel proteins. Carrier proteins never allow free exchange across the membrane because they never create a continuous passage between the inside and outside of the cell.
93) This is discussed in the "5.4 Protein-Mediated Transport" section of the chapter.
94) Fick's law of diffusion determines the rate of diffusion. The flux of a molecule is the rate of diffusion per unit surface ar membrane.
Fick's: Rate of diffusion = concentration gradient × membrane permeability × surface area
Flux = concentration gradient × membrane permeability
95) 1. the diameter of the central pore
2. the electrical charge of the amino acids that line the channel
96) Both involve binding of substrate to a carrier, but facilitated is passive, moving solutes down their concentration gradients, whereas active requires ATP and can move solutes against their concentration gradients.
97) All forms of transport require energy, because something is being moved.
A. Passive transport uses the potential energy present in the living cell to move molecules in the energetically favorable downhill direction (with concentration gradients).
B. Active transport uses the energy transferred by the ATP molecule, to move molecules in the energetically unfavorabl direction (against concentration gradients).
C. Vesicular transport uses the energy of the ATP molecule also, to move large molecules or large quantities of molecul
98) Cotransport is the moving of more than one kind of molecule at one time. Antiport is cotransport of two or more solutes in opposite directions across the membrane. Symport is cotransport of two or more solutes in the same direction across the membrane.
99) Both ultimately depend on the energy of ATP, but dependence is indirect in secondary, direct in primary.
100) Secondary active transport uses the energy released from moving one substance down its concentration gradient to push other substances against their concentration gradient. ATP is used to create the chemical disequilibrium (or concentration gradient) for the first substance.
101) See Figure 5.16 and 5.17 in the chapter.
102) This is discussed in the "Osmosis and Tonicity" section of the chapter.
103) Dynamic indicates that materials are constantly moving from compartment to compartment, but steady state implies there is no NET movement between the compartments.
104) 1. connect membrane to the cytoskeleton to maintain cell shape
2. create cell junctions that hold tissues together
3. attach cells to the extracellular matrix by linking cytoskeleton fibers to extracellular collagen and other protein fibers
105) See Figure 5.11 in the chapter.
106) See Figure 5.12 in the chapter.
107) Higher concentrations of cholesterol in the cell membrane reduce membrane permeability to water.
108) See Figure 5.19 in the chapter.
109) See Table 5.6 in the chapter.
110) See Table 5.4 in the chapter.
111) A. Chemical reaction equilibrium is achieved in reversible reactions when the rate of the forward reaction equals the rat reverse reaction. At this state there is no net change in the concentration of reactants and products in the system. This d mean that concentrations are equal.
B. Chemical equilibrium occurs when the concentration of a particular solute in one location equals that in another. Typ locations compared are intracellular vs. extracellular.
C. Osmotic equilibrium occurs when total solute concentration is the same, though chemical disequilibrium may exist.
112) Make sugar syrup for Patrick by heating a small amount of water with a generous amount of sugar. The sugar diffuses through the water as it dissolves, and this will occur much quicker in warm water (diffusion rate increases with increasing temperature). Then add the syrup to his iced tea and serve.
113) A fluid is a substance that flows. Bulk flow is movement of a fluid, usually within a body compartment. Liquids and gases are fluids, and they flow. Gases are compressible, but liquids are not.
114) C
115) B
116) B
117) D
118) Mechanically gated (in sensory cell receptor potentials), voltage-gated (in nerve and muscle action potentials), and chemically gated (in neuromuscular synaptic transmission).
119) Answers will vary. Controlled variables may include temperature, pH, composition and volume of solvent or medium, amount of solute added. Solutes could be soluble dyes of different molecular weight, and rate of diffusion could be estimated by observing the extent of coloration around a dye crystal at specified intervals.
120) Kidney cells may have fewer open channels through which water can pass, and/or they may have more cholesterol in their membranes.
121) Molarity is the number of molecules per liter of solution, while osmolarity is the number of independent particles per liter. The ionization of salt in water illustrates the importance of this distinction: one mole of sodium chloride dissociates to produce a total of two moles of particles (one mole Na+ and one mole Cl-), or two osmoles. Osmosis is diffusion of water. A one molar solution of sodium chloride (two osmolar) produces higher osmotic pressure than a one molar solution of glucose, which does not dissociate.
122) Osmolarity refers to the concentration of individual particles in solution. Tonicity refers to the behavior of a cell in a solution. They are similar in that both are related to particles in solution. They are different in that osmolarity depends only on the total concentration of particles in solution, whereas tonicity depends on nature of the particles (i.e., are they penetrating or nonpenetrating) as well as on the concentration of the different particles.
123) See Figure 5.26b in the chapter.
124) This is easier to answer if all three solutions are described in equivalent terms. Solution b is 2 osmolar, because of the dissociation of sodium and chloride. Solution c is 0.9 osmolar.
A. iso D. hyper
B. iso E. hyper
C. hypo F. hypo
125) Because the kidney is failing to filter particles out of the blood effectively, the plasma becomes hypertonic or hyperosmotic in comparison to the intracellular compartment of the blood cell. Since the cell membrane is impermeable to the ions, but permeable to water, water will leave the cell to try to balance the tonicity and osmolarity with the plasma and in the process the cell will shrink.
126) A. Hyposmotic, hypotonic. The cell swells. By Rule 5 in Table 5.8 in the chapter, hyposmotic solutions are always hypot because the intracellular solutes are mainly nonpenetrating (Rule 1) thus there will be a net flow of water into the cell.
B. Hyperosmotic, hypotonic. The cell swells. Urea is a penetrating solute, so some urea will move into the cell down its concentration gradient. This will increase the osmolarity inside the cell, causing a net flow of water into the cell.
C. Isosmotic, hypotonic. The cell swells. Urea is a penetrating solute, so there will be a net movement of urea into the ce raising the osmolarity and causing a net flow of water into the cell.
D. Isosmotic, hypotonic. The cell swells. Urea will penetrate the cell, raising the osmolarity and causing a net flow of wa the cell.
E. Isosmotic, isotonic. No change in cell size. Sodium and chloride are nonpenetrating solutes, so there will be no net io across the membrane. Because there is no osmotic pressure, there will also be no net flow of water.
F. Hyperosmotic, isotonic. No change in cell size at equilibrium. Initially water leaves the cell due to the higher osmolar outside the cell. Then, because there is a concentration gradient for urea, urea will enter the cell, increasing its osmolarit bringing some water into the cell. The nonpenetrating solute concentrations in cell and solution initially are equal, there there will be no net movement of water at equilibrium.
G. Hyperosmotic, hypertonic. The cell shrinks. There are no penetrating solutes, and water exits due to the higher osmo
127) In osmoles, solution A is 0.3 OsM and solution B is 0.3 OsM (because sodium and chloride dissociate into separate particles). The solutions are isosmotic, and there is no net water flow.
128) In osmoles, solution A is 0.4 OsM and solution B is 0.3 OsM. Solution A is hyperosmotic, so there will be a net flow of water into solution a until equilibrium is established.
129) The transport maximum occurs when all carrier binding sites are filled with substrate. At this point adding more substrate will no longer increase the rate of transport. In order to increase the capacity and raise the maximum rate of transport, some cells can increase the number of carrier proteins in the membrane.
130) Low concentrations of potassium in the blood is a condition called hypokalemia. Interstitial fluids would similarly become low in K+ . As the resting potential of nerve and muscle cells depends primarily on extracellular K+ concentration, the potential would be altered. Decreased extracellular K+ would increase the concentration gradient for movement of K+ out of the cells, which would gradually hyperpolarize the potential as positive ions exit and make the cells less excitable (farther from threshold).
131) Potassium is a cation that leaves the cell during an action potential or depolarization of a muscle or nerve cell, and the muscle or nerve cell needs to move potassium back into the cell to allow the cell to repolarize and relax. If there is a deficiency in potassium, muscle and nerve cells may take longer to repolarize and therefore relax, so increasing your dietary intake of potassium may help cells repolarize quicker.
132) Active transport of chloride is impaired, in the airways, sweat glands, and pancreas. The affected epithelia are involved in production of sweat and mucus. Thus, the respiratory, integumentary, and digestive systems are affected. Treatments include replacement of pancreatic digestive enzymes, which are blocked from secretion by the mucus buildup in secretory ducts, and respiratory therapies to loosen mucus in the airways and treat recurring infections. Gene therapy is being explored as well. Median survival is nearly 40 years as of the publication date of the textbook. Causes of death can be related to malnutrition and respiratory illness. This is a genetic disease, in which the gene coding for the chloride transporter is abnormal.
133) Similar to the myelin membrane around nerve cells–good insulators.
134) Quantitative chemical analysis would determine osmolarity. To determine tonicity, drop the cells into various solutions and observe the cells' response under the microscope.
135) ATP dependent potassium gates keep the calcium channels opened, thus allowing the exocytosis of insulin when there is enough glucose getting into the cell. When glucose levels drop and the amount of ATP the beta cell is making drops, it eventually loses the energy to keep the Ca2+ gates open, therefore exocytosis of insulin is prevented.
136) Equivalent osmolality to a 0.11% solution of glucose
137) 25 g glucose/1000 mL solution × 4 mL solution/min = 0.1 g glucose/min
138) 0.48 × 145 lb × 1 kg × 1 L = 31.64 L 2.2 lb 1 kg
139) 4.5 g NaCl into 950 mL of distilled water.
Adjust the pH if necessary to 7.4, then add more distilled water, up to 1000 mL.
0.45 g NaCl × 1 mol NaC1 × 2 osmol × 1000 mL = 0.154 osmoles/L
100 mL soln 58.44 NaCl 1 mol 1 L
140) The cell has two separate membrane transport molecules, one specific for glucose and the other for fructose. The transp become saturated somewhere between the concentrations of 0.5 mM and 1.0 mM, thus any higher concentration of thes sugars produces no further increase in transport.
141) A. 300 mOsM NaCl × 1 L = 300 mOsmoles NaCl.
450 mOsM glucose × 2 L = 900 mOsmoles glucose.
Total solutes = 900 mOsmoles + 300 mOsmoles = 1200 mOsmoles.
Total volume = 1 L + 2 L = 3 L. 1200 mOsmoles/3 L = 400 mOsM solution.
B. 300 mOsmoles/3 L = 100 mOsM NaCl.
C. 900 mOsmoles/3 L = 300 mOsM glucose.
D. Solution is hyperosmotic. Glucose is a penetrating solute, so glucose diffuses into the cell, raising the osmolarity, cau water to diffuse into the cell. The cell swells. Thus, the solution is hypotonic.
142) Nurse Cameron should make her solution contain only nonpenetrating solutes, i.e., she should use NaCl but not glucos urea.
10 L (0.290 Osmoles/L) (1 mole NaCl/2 Osmoles) (58.5 g/1 mole NaCl) = 84.8 g NaCl.
She should add 84.8 g NaCl to about 9.5 L distilled water, mix until dissolved, adjust the pH if necessary to 7.4, then ad water to a final volume of 10 L.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Cells that respond to signals are usually called
A) targets.
B) contacts.
C) junctions.
D) receivers.
E) responders.
2) Which is NOT a basic method of cell-to-cell communication?
A) nerve and blood-transported signals
B) contact-dependent signals
C) cytoplasmic transfer of signals
D) diffused chemical signals
E) mechanical signals
3) The most significant difference between a paracrine and an autocrine is the
A) method of transport.
B) cell that responds to it.
C) route of transport.
D) cell that releases it.
E) There are no differences–they are the same.
4) Neurotransmitters and neurohormones both
A) affect only cells with a specific receptor.
B) are released by neurons.
C) travel in the blood to their target cell.
D) A and B
E) are produced by all cells.
5) Why do some normal cells fail to respond to a chemical signal?
A) Some cells are completely without receptors.
B) Some cells are completely without ligands.
C) Chemical signals are only delivered to specific cells.
D) Some cells lack the appropriate receptors.
E) Signal chemicals often break down before reaching a distant target. 5)
6) Receptor molecules on the surface of a cell
A) determine that cell's response.
B) allow a particular ligand to bind.
C) bind to all ligands.
D) A and B
E) A and C
7) Receptor molecules are located
A) in the cytosol.
B) in the nucleus.
C) on the cell surface.
D) in the outer cell membrane.
E) in all of these places.
8) Down-regulation may allow a target cell to
A) increase its number of receptors for a ligand.
B) increase its binding affinity for a ligand.
C) decrease its number of receptors for a ligand.
D) B and C.
9) Inositol triphosphate is a second messenger that
A) uses all of the mechanisms.
B) binds to the calcium channel of the endoplasmic recticulum.
C) involved in the release of calcium into the extracellular fluid.
D) involved in the storage of calcium into the endoplasmic reticulum.
10) Lipophilic hormones
A) function by activating cAMP.
B) cannot diffuse through the cell membrane.
C) usually bind to receptors inside the cytoplasm or nucleus.
D) function by way of a second messenger system.
E) usually bind to receptors on the surface of the cell.
11) When adenylyl cyclase is activated,
A) cAMP is broken down.
B) calcium ions are released from intracellular stores.
C) cAMP is formed.
D) steroids are produced.
E) protein kinases are metabolized. 11)
12) Second messenger molecules directly
A) increase intracellular calcium concentration.
B) change enzyme activity.
C) change the regulation of ion channels.
D) change regulation of gene activity.
E) All of the answers are correct.
13) Cyclic AMP activates
A) hormone receptors.
B) adenylyl cyclase.
C) protein hormones.
D) a G protein.
E) protein kinase A.
14) Diacylglycerol is produced from
A) phospholipase C.
B) phosphatidylinositol bisphosphate.
C) cyclic AMP.
D) a G protein.
E) protein kinase A.
15) Usually, cytokine binding usually activates
A) tyrosine kinase.
B) citrulline kinase.
C) calmodulin kinase.
D) intrinsic transducers.
E) JAK kinase.
16) What by-product results during the production of nitric oxide?
A) arginine
B) citrulline
C) carbon dioxide
D) carbon monoxide
E) nitric oxide synthase
17) An integrating center
A) is an electrical and/or chemical signal that travels to the effector.
B) evaluates incoming signals and compares it with the setpoint.
C) is the minimum stimulus that must be achieved to set the reflect response in motion.
D) is the disturbance or change that sets the pathway in motion.
18) Which is a difference between endocrine and neural control systems?
A) nature of the signal
B) specificity
C) speed
D) duration of action
E) All of the answers are correct.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the term with its description.
19) the desired target value for a parameter
20) receives information about the regulated variable and initiates a response A) integrating center
setpoint
21) the minimum stimulus to trigger a response in motion
22) the cell or tissue that performs the change
23) continuously monitors its environment for a specific variable
sensory receptor
effector
threshold
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
24) Peripheral cells sensitive to the presence of hormones are called . 24)
25) A few gases are known to act as signal molecules, including , , and . 25)
26) Before nitric oxide was identified, its action was observed in and it was given the name . 26)
27) can be caused by alterations in receptors or by problems with G protein or second messenger pathways. 27)
28) Lipid signal molecules that act in a paracrine fashion and combine with G-protein coupled receptors include and . 28)
29) is a process by which an extracellular signal molecule, called the , activates a membrane receptor that in turn alters intracellular molecules, called the , to create a response. 29)
30) A gap junction forms when opposing membrane-spanning proteins called on two adjacent cells unite, creating a protein channel that is capable of opening and closing.
30)
31) A chemical that is secreted by a cell to act on cells in its immediate vicinity is called a(n) . 31)
32) If the signal molecule acts on the cell that secreted it, the chemical is called a(n) 32)
33) All molecules secreted by nerve cells (neuromodulators, neurotransmitters, and neurohormones) are known as 33)
34) are molecules that bind to the receptor in such a way that they block competing ligands from binding and prevents the receptor from responding. 34)
35) If the concentration of a ligand decreases, the target cell may insert more receptors into the cell membrane in an attempt to keep its response at a normal level, in a process known as . 35)
36) The nervous system has a role in preserving the "fitness" of the 36)
37) The link membrane receptors to either ion channels or to enzymes located on the cytoplasmic side of the membrane.
38) Many second messenger systems activate , enzymes that transfer a phosphate group from ATP to a protein. The phosphorylation of proteins sets off a series of intracellular events that lead to the ultimate cellular response.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
39) Explain how epinephrine can cause intestinal blood vessels to constrict and cause skeletal muscle blood vessels to dilate.
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
40) To maintain , the body uses a combination of simple diffusion across small distances; wide spread distribution of molecules through the circulatory system and rapid, specific delivery of messages by the nervous system.
41) Most long-distance communication between cells takes place through the and systems with their combination of chemical and electrical signals.
42) An intracellular signal molecule that translates a signal from a neurotransmitter or hormone into an intracellular response is called a .
43) The secretion of the hormone insulin in response to changes in blood glucose level is an example of a(n) reflex.
44) Homeostatic regulation usually involves a(n) that is sensitive to a particular stimulus (variable) and a(n) whose activity has an effect on the same stimulus.
45) When epinephrine combines with alpha adrenergic receptors on smooth muscle in intestinal blood vessels, the blood vessels ; however, when epinephrine binds to beta2 adrenergic receptors on certain skeletal muscle blood vessels, the blood vessels .
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
46) Describe the four basic methods of cell-to-cell communication.
47) Compare and contrast down-regulation and desensitization.
48) In your own words restate and explain Cannon's four postulates for maintaining homeostasis.
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
49) What is the half-life of a signal? 49)
50) What is an orphan receptor?
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
51) The membrane receptors and second messengers often activate
A) a membrane receptor molecule.
B) ATP.
C) cholesterol.
D) a hormone.
E) a protein kinase.
52) The most important factor determining whether a signal molecule will bind to cell-surface or intracellular receptors is the
A) size of the ligand.
C) lipid solubility of the ligand.
53) An ion widely important in intracellular signaling is A) cobalt.
B) sodium.
C) potassium.
D) calcium.
E) chloride.
B) location of the receptor molecule.
D) size of the receptor molecule.
54) When calcium becomes available inside a cell, it comes from
A) extracellular fluid.
B) intracellular storage.
C) A and B.
D) It is always available as a major cytosol cation.
55) One intracellular calcium-binding protein is
A) calmodulin.
B) calcitonin.
C) IP3.
D) calcitriol.
E) nitric oxide.
56) Protein receptors exhibit
A) competition.
B) saturation.
C) specificity.
D) B and C.
E) A, B, and C. 56)
57) The binding of lipophilic messengers, such as steroid hormones, to their receptors triggers
A) adenylyl cyclase activation.
B) G protein inhibition.
C) cyclic nucleotide formation.
D) protein kinase activation.
E) gene transcription.
58) Both insulin and glucagon are peptide hormones that target liver cells. The response of the target cells to each of these two hormones is opposite. This information implies that
A) the two hormones bind to different cell surface receptors.
B) one hormone binds to a receptor on the cell membrane and the other to an intracellular receptor.
C) each of the two hormones uses a different second messenger.
D) both hormones interact with receptors at the cell nucleus.
E) A and C.
59) Which is NOT an example of homeostasis?
A) Decreased body temperature stimulates a neural response that increases body temperature.
B) Increased blood sugar stimulates the release of a hormone from the pancreas that stimulates the liver to store blood sugar.
C) Increased estrogen during the menstrual cycle increases the number of progesterone receptors in the uterus.
D) Increased blood pressure in the aorta stimulates mechanisms to lower blood pressure.
E) Increased blood calcium levels stimulates the release of a hormone that lowers blood calcium levels.
60) Homeostatic control that takes place at the tissue or cell by using paracrine or autocrine signals is called
A) down-regulation.
C) Cannon's law.
B) local control.
D) reflex control.
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
61) A physiological parameter which is regulated in an up-down fashion by signals that are always present but change in intensity is said to be under .
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
62) Insulin increases glucose transport across the cell membrane of an adipocyte, but not across the membrane of a liver cell. How can one hormone have two different effects?
63) Describe the four classes of membrane receptor molecules.
64) What general action is shared by about half of the medical drugs currently in use?
65) Describe the signal molecule derivatives of arachidonic acid.
66) Describe or diagram the basic pattern of a biological signal transduction pathway.
67) What are NSAIDs, what is their function, and what are some drawbacks to their use?
68) Define tonic control and give a physiological example.
69) Design a flow chart or concept map to summarize the information in the text under the heading "Cell-to-Cell Communication." This chart should make clear the four basic methods of cell-to-cell communication, and the relevance of and distinction between paracrine, autocrine, neurocrine, and cytokine chemicals.
70) Compare and contrast hormones, neurotransmitters, and neurohormones.
71) Briefly explain the effects of the hormone insulin on glucose transport. What is diabetes mellitus? How are types 1 and 2 different? Why do insulin injections help one type but not the other?
72) Compare and contrast neural and endocrine control.
73) Compare and contrast neural, neuroendocrine, and endocrine reflex pathways.
74) Nobel Prizes were awarded to the discoverers of G proteins, the G protein-coupled adenylyl cyclase-cAMP system, and nitric oxide. Summarize each of these, and explain the importance of these discoveries to our understanding of signal pathways.
75) Food items are occasionally shown to offer protective effects to those who eat them. Garlic, for example, may improve heart health. The pungency of garlic is due to sulfur-containing compounds. Explain how these compounds are good candidates for garlic's heart benefits.
76) "Too much of a good thing can hurt you." "It's all good." We've heard phrases like this, and know that they contain some truth. For example, both water and sunshine can harm us. Not enough cholesterol in the body is worse than too much. What otherwise poisonous gas has recently been shown to be a signal molecule? What does it do in the body?
77) Receptors in cell signaling are not to be confused with receptors that activate a reflex arc. Explain the difference, using specific examples.
78) You are part of a research team designing a robot for competition. Your robot needs to be able to respond to painful stimuli like stepping on broken glass. What type of human control system will you model your robot after? Explain your reasons for choosing it.
79) The fight-or-flight reaction prepares an animal to respond to a threatening situation, by either fighting or running away. One aspect of this response is changes in blood flow such that the skeletal muscles and heart receive higher blood flow (vessels dilate) while digestive organs receive less (vessels constrict). Which signal molecule(s) is/are involved in this response, and how do they produce these changes in blood vessels? Explain how this example illustrates one or more of the following concepts: multiple ligands for one receptor, multiple receptors for one ligand, agonists and antagonists.
80) Blood glucose levels are kept fairly steady in healthy people through the action of the hormones insulin and glucagon. Insulin decreases blood glucose by increasing glucose uptake by cells, whereas glucagon increases blood glucose by increasing release of glucose from cells. Describe these hormone actions as simple reflex pathways, identifying the stimulus, integrating center, efferent pathway, and response.
81) Brain cells are able to absorb glucose independent of insulin. What must be missing from brain cells compared to most other cell types? One of the risks of diabetes mellitus is diabetic coma, which results when insufficient glucose is available to the brain. Would you expect diabetic coma to be triggered when insulin is low or high? Explain. (Hint: Think about regulation of the number of glucose transporters in brain cells and how the hyperglycemia present prior to insulin treatment may affect transporters.)
82) Asthma is a respiratory disorder characterized by constriction of airways and mucus production which makes it very difficult to breathe. The constriction of airways, mucus production, and altered gene expression in the cells lining the airways of asthmatics is due to increased release of neurotransmitter acetylcholine. Explain how a single molecule can have such a large and diverse effect in a single cell.
Answer Key
Testname: UNTITLED25
1) A
2) E
3) B
4) D
5) D
6) D
7) E
8) C
9) B
10) C
11) C
12) E
13) E
14) B
15) E
16) B
17) B
18) E
19) B
20) A
21) C
22) B
23) A
24) targets
25) nitric oxide, carbon monoxide, hydrogen sulfide
26) endothelial cells (blood vessel lining), endothelial-derived relaxing factor (EDRF)
27) Diseases
28) eicosanoids, sphingolipids
29) Signal transduction, first messenger, second messenger
30) connexins
31) paracrine
32) autocrine
33) neurocrines
34) Antagonists (or Competitive inhibitors)
35) up-regulation
36) internal environment
37) G proteins
38) protein kinases
39) Epinephrine can bind to different isoforms of the adrenergic receptor. Epinephrine binds to alpha receptors on the intestinal blood vessels and beta2 receptors on the skeletal muscle blood vessels (see Fig. 6.14).
40) homeostasis
41) nervous, endocrine
42) second messenger
43) simple endocrine
44) receptor or sensor or sensory receptor, target or effector
45) constrict, dilate
46) The cells can:
1. transfer signal molecules to adjacent cells through gap junctions
2. use contact-dependent signals, which rely on interactions between cell surface molecules on different cells
3. use locally acting chemicals, called paracrines, autocrines, or neuromodulators
4. use long-distance means, which rely on combinations of electrical and chemical signals
47) Either the number of receptors decreases or desensitization in which the binding affinity of the receptors for the ligand decreases. In both cases the result is a lessened response of the target cell even though the concentration of the signal molecule remains high.
48) This is discussed in the "Cannon's Postulates Describe Regulated Variables and Control Systems" section of the chapter.
49) the time required for a signal to lose half its activity
50) a receptor that has no known ligand
51) E
52) C
53) D
54) C
55) A
56) E
57) E
58) E
59) C
60) B
61) tonic control
62) The two types of cells differ either in the receptors on their cell membranes or in the signal transduction that occurs after binding of insulin.
63) Ligand-gated receptors are ion channels, integrins are linked to the cytoskeleton, receptor-enzymes activate intracellular enzymes, G protein-coupled receptors involve activation of G proteins. See Figure 6.3.
64) These drugs act on membrane receptor proteins.
65) Leukotrienes are secreted by certain types of white blood cells and play a role in asthma and anaphylaxis. Prostanoids, including prostaglandins and thromboxanes, have a variety of target tissues and effects.
66) See Figure 6.4 and the "Membrane Proteins Facilitate Signal Transduction" section in the chapter.
67) Nonsteroidal anti-inflammatory drugs, such as aspirin and ibuprofen, prevent inflammation. They have side effects such as bleeding in the stomach.
68) Tonic control regulates physiological parameters in an up-down fashion. An example is the neural regulation of blood vessel diameter (see Fig. 6.15).
69) This is discussed in the "Cell-to-Cell Communication" section in the chapter.
70) See Figure 6.1 and the "Long-Distance Communication May Be Electrical or Chemical" section in the chapter.
71) Insulin promotes glucose transport into most types of cells. Diabetes mellitus results when insulin regulation of blood glucose concentrations is impaired. In type 2, the pancreas fails to produce insulin, whereas in type 2 but target cells fail to respond properly.
72) See Table 6.2 in the chapter.
73) See Table 6.3 in the chapter.
74) G proteins are coupled to hundreds of different receptors on cells. These are receptors that bind ligands such as hormones, neurotransmitters, and molecules important in sensory systems. Activated G proteins open ion channels or alter enzyme activity. The G protein-coupled adenylyl cyclase-cAMP system was the first signal transduction pathway discovered, and therefore paved the way for our understanding of signal transduction. cAMP is the second messenger in many signaling systems. Nitric oxide functions as a neurotransmitter, neuromodulator, and paracrine important in cardiovascular regulation.
75) When sulfur compounds are metabolized, hydrogen sulfide may be produced. This gas has recently been shown to be a signal molecule that relaxes blood vessels.
76) Carbon monoxide is one of the gaseous signal molecules. It activates guanylyl cyclase and cGMP in smooth muscle and neural tissue.
77) Receptor molecules are proteins on or in cells that bind to ligands. This binding triggers a response within a cell, to the signaling chemical. For example, this is how a hormone exerts its effect on a target cell. Receptors in a reflex arc are not protein molecules but rather are entire cells, parts of cells, or multicellular structures. These receptors cause a signal to be sent to an integrating center, which may or may not then initiate a response usually involving many cells. For example, a blood pressure receptor detects a decrease in pressure, and sends a neural signal to cardiovascular integrating centers to trigger a vascular response to increase pressure.
78) One should choose the nervous system and a simple neural reflex because of its ability to rapidly respond and remove the robot from potential harm. The response will be specific for the region in harm and the robot will get a sense of the intensity of pain via a change in the frequency of signaling.
79) The signal molecules are norepinephrine and epinephrine. Both of these chemicals bind to the same adrenergic receptors (multiple ligands) and have the same effect on their receptors, so they are agonists. When alpha-adrenergic receptors are activated in digestive organs, blood vessels constrict. When beta-adrenergic receptors are activated in skeletal and cardiac muscles, blood vessels dilate (multiple receptors).
80) Stimulus: increased blood glucose. Integrating center: endocrine cell (in pancreas). Efferent pathway: insulin secretion. Response: increased cellular uptake of glucose. Feedback: negative. Stimulus: decreased blood glucose. Integrating center: endocrine cell (in pancreas). Efferent pathway: glucagon secretion. Response: release of glucose from cells. Feedback: negative.
81) Brain cells lack the insulin receptors that stimulate glucose uptake, because an insulin-independent mechanism for glucose uptake is present. Brain cells will down-regulate their glucose transporters during periods of hyperglycemia. When insulin levels increase during treatment of type I diabetes, promoting lower concentrations of glucose in the blood, this can trigger diabetic coma because the brain cells have too few glucose transporters for the new, lower levels of blood glucose.
82) See Figures 6.5, 6.6 and 6.8; signal amplification.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Which is NOT a method of hormone action?
A) control of gene expression and protein synthesis
B) control of electrical signaling pathways
C) control of ion or molecule transport across cell membranes
D) control of enzymatic reaction rates
E) All are methods of hormone action.
2) When a catecholamine or peptide hormone binds to receptors on the surface of a cell,
A) second messengers are activated.
B) the cell membrane becomes less permeable.
C) the hormone is transported to the nucleus where it alters the activity of DNA.
D) the cell becomes inactive.
E) None of the answers are correct.
3) The link between a first messenger and a second messenger in a cell that responds to peptide hormones is usually
A) cGMP.
B) a G protein.
C) calcium.
D) adenylyl cyclase.
E) cAMP.
4) When adenylyl cyclase is activated,
A) steroids are produced.
B) cAMP is broken down.
C) protein kinases are metabolized.
D) cAMP is formed.
E) calcium ions are released from intracellular stores.
5) Typically, when steroid hormones bind to their receptors,
A) protein kinases are activated.
B) cyclic nucleotides are formed.
C) G proteins are inhibited.
D) gene transcription may increase or decrease.
E) adenylyl cyclase is activated.
6) Steroid hormones are synthesized in the of the cell.
A) smooth endoplasmic reticulum
B) nucleus
C) mitochondria
D) rough endoplasmic reticulum
E) Golgi apparatus
7) Which statement about peptide hormones is FALSE?
A) Peptide hormones are first synthesized as prohormones.
B) Peptide hormones interact with receptors on the surface of their target cells.
C) Peptide hormones in the bloodstream are always bound to carrier proteins.
D) Prohormones can be activated before their release by post-translational modification.
E) Peptide hormones remain in circulation for relatively short periods of time.
8) Which hormone is NOT an amino acid derivative?
A) thyroid-stimulating hormone
B) melatonin
C) norepinephrine
D) epinephrine
E) thyroid hormone
9) The majority of hormones in the body are
A) amino acid-derived hormones.
B) steroid hormones.
C) neurohormones.
D) peptide hormones.
E) All of the hormones are present in equal amounts in the body.
10) The most complex endocrine responses involve the
A) hypothalamus.
B) thyroid gland.
C) adrenal glands.
D) thymus.
E) pancreas.
11) The posterior pituitary gland secretes
A) MSH.
B) FSH.
C) ACTH.
D) TSH.
E) Vasopressin (ADH).
12) The pituitary hormone that controls the release of hormones from the adrenal cortex is A) TSH. B) STH. C) LH. D) FSH. E) ACTH. 12)
13) The pituitary hormone that controls hormone synthesis and release from the thyroid gland is A) FSH. B) ACTH. C) TSH. D) LH. E) STH. 13)
14) The pituitary hormone that stimulates milk production by the mammary glands is
A) prolactin.
B) FSH.
C) TSH.
D) growth hormone.
E) ACTH. 14)
15) The pituitary hormone that stimulates cell growth and metabolism in many tissues is
A) somatotropin.
B) insulin.
C) ACTH.
D) MSH.
E) prolactin.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match each term with the appropriate description.
16) lipophobic molecule that interacts with receptors on cell surface
17) site of vasopressin synthesis
18) true endocrine gland of epithelial origin
19) cannot be stored in secretory vesicles
20) derivative of tyrosine
21) storage and release site for oxytocin
Match each hormone with its main source.
22) adrenal medulla
23) pancreas
24) thyroid
25) anterior pituitary
26) adrenal cortex
27) pineal
peptide hormone
hypothalamus
anterior pituitary
amino acid-derived hormone
posterior pituitary
steroid hormone
insulin
calcitonin
aldosterone
melatonin
prolactin
epinephrine
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
28) The study of hormones is known as the field of 28)
29) The of a hormone is a measure of how long a hormone is active in the body. 29)
30) A circulatory route that has two sets of capillaries connected in series by a set of small veins is known as a . 30)
31) The posterior pituitary gland is also known as the . 31)
32) The anterior pituitary gland is also known as the 32)
33) The hormones that regulate the male and female reproductive organs are collectively called 33)
34) is a decrease in the number of receptors of target cells in order to diminish the responsiveness to excess hormone. 34)
35) The gland sits atop the kidney. 35)
36) The outer portion of the adrenal gland is called the . 36)
37) The inner portion of the adrenal gland is called the . 37)
38) The adrenal cortex produces a steroid hormone called that controls blood pressure homeostasis and another steroid hormone called that controls blood glucose levels. 38)
39) The term for two hormones that have greater than additive effects have a(n) effect. 39)
40) The term that describes the need for one hormone to be present for a second hormone to produce a full effect is called 40)
41) Two hormones that have opposing effects are called . 41)
42) Loss of cell mass is called which can cause an organ or gland to shrink due to lack of use 42)
43) The term for any hormone that controls the secretion of another hormone is a . 43)
44) The hormones of the anterior pituitary are controlled by trophic hormones from the . 44)
45) Trophic hormones reach the pituitary through the . 45)
46) pathologies arise in the last endocrine gland in a complex reflex pathway. 46)
47) A is a problem with hormones from the anterior pituitary. 47)
48) Chemical signals released into the blood by neurons are called 48)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
49) When stimulated by a particular hormone, there is an increase in the activity of G proteins in the membrane. The hormone is probably
A) aldosterone.
B) testosterone.
C) a peptide.
D) estrogen.
E) a steroid.
50) After a hormone has exerted its effects, it typically
A) is inactivated or removed from the blood.
B) is absorbed by the gland that secreted it.
C) is absorbed by its target cell.
D) continues to act until an opposing hormone is secreted.
E) increases its half-life.
51) Hormones are not typically considered to be cytokines because hormones are like cytokines.
A) synthesized in advance and stored, not
B) secreted into the blood, not
C) not effective in small amounts
D) secreted by cells, not
E) not peptides
52) In a simple endocrine reflex, the endocrine cell is the A) target.
B) sensor and integrating center.
C) integrating center only.
D) integrating center and target.
E) sensor only.
53) Synergism occurs when
A) a hormone can exert its full effects only in the presence of another hormone.
B) one hormone stimulates the secretion of a second hormone.
C) hormones working together produce a smaller effect than predicted.
D) one hormone inhibits the release of a second hormone.
E) hormones working together produce a larger effect than predicted. 53)
54) Hormones acting through signal transduction pathways stimulate a response compared to hormones that produce genomic effects.
A) slower B) faster C) equal
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
55) A cell's response to a hormone primarily depends on and . 55)
56) The signal molecule produced by one animal that may affect the behavior of another animal of the same species is the 56)
54)
57) A signal molecule that is secreted into the external environment, instead of into the blood, is called a(n) 57)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
58) Describe the classic steps for identifying an endocrine gland. Are these steps practical for identifying the sources of all the hormones we know of today? Explain.
59) List and explain two ways hormones affect their targets.
60) List the three types of hormone interactions and provide an example of each.
61) Explain the differences among the terms paracrine, autocrine, hormone, and cytokine.
62) What are two benefits of having a portal system that connects the hypothalamus with the anterior pituitary gland? Are there any other endocrine glands connected by a portal system?
63) A given hormone generally has the same effect on different target tissues. Is this statement TRUE or FALSE? Defend your answer.
64) What normally stops hormone action, and why is this important?
65) How does the embryological origin of the two distinct parts of the pituitary gland relate to the control of secretion and the types of hormones produced?
66) Explain the concept of evolutionary conservation of hormone activity, and how recognition of that phenomenon has influenced hormone therapies.
67) One hypothalamic hormone stimulates release of a pituitary hormone which stimulates release of an adrenal hor Fill in the names of the hormones below. If a tumor in the adrenal gland resulted in hypersecretion, how would t affect the relative levels of hormone produced from each source? Which type of reflex pathway is involved?
Hormone Source
Tumor effects
Hypothalamus increase decrease
Anterior pituitary increase decrease
Adrenal cortex increase decrease
68) Dexamethasone is a drug used to decrease the secretion of ACTH from the anterior pituitary gland. Two patients with hypersecretion of cortisol are given dexamethasone. Anika's cortisol secretion level decreases to normal after the medication, but Maria's cortisol secretion remains increased. Which patient has primary hypercortisolism, also known as Cushing's syndrome? Explain your reasoning.
69) The following statement contains three parts that are either TRUE or FALSE. Address ALL THREE parts of the statement explaining either why it is TRUE or why it is FALSE. Neurohormones from the anterior pituitary are called trophic because their release is stimulated by a releasing hormone from the hypothalamus.
70) Ibrahim is suffering from hypothyroidism. What is hypothyroidism? How could his physician determine whether the malfunction is in the hypothalamus and pituitary or at the level of the gland itself?
71) Naura is a 15-year-old girl but has never had a menstrual period, though she has other signs of puberty such as breasts and pubic and axillary hair. During a pelvic exam her physician determines that she has no uterus. Blood tests reveal that she has increased levels of testosterone in her blood, similar to that expected in young adult males. Name two typical sources of testosterone. Given the lack of a uterus, what is the likely source of testosterone in this case? She might have which pathology or mutation? (Hint: Consider general principles of hormone secretion and action.) Why is there no uterus? What genetic test may confirm this suspicion?
72) Your roommate Xia has just found out her mother has high cholesterol. Knowing that health problems often run in families, Xia has decided to eliminate cholesterol from her diet. Her goal is to have no cholesterol in her body. She has asked you for advice on achieving this goal. Is her goal realistic? Explain. What information should you give her to help her establish a more realistic goal? Assuming she could banish cholesterol from her body, what would be the endocrine consequences?
73) Thyroid hormone secretion decreases with age. Treatment with thyroid-releasing hormone is less effective in younger patients, while treatment with thyroid hormone is more effective in younger patients. What name is given to the condition of decreased thyroid hormone secretion? What related hormones are likely t decrease as well? Propose an explanation for the loss of responsiveness to the releasing hormone. Propose an explanation for the increased responsiveness to treatment with thyroid hormone (consider both how hormones affect target cells and how hormone action is halted).
74) There are two forms of diabetes: diabetes mellitus (abnormal regulation of cellular uptake of glucose by the hormone insulin) and diabetes insipidus (abnormal regulation of water loss in the urine by the hormone antidiuretic hormone or ADH). In each case, there are two similar explanations for the resulting pathology. What are they? (Hint: Consider general principles of hormone action.)
75) The total area of a cell membrane in a single fat cell is 104 mm2, there is one insulin receptor per 1 mm2 of membrane, and 1 mm2 of cell membrane contains 106 phospholipid molecules.
1. How many insulin receptors are in a fat cell?
2. How many phospholipids molecules are in a fat cell?
3. How many phospholipid molecules are there for each insulin receptor?
4. What general principle of hormone action does your answer support?
76) Selena wants to protect virgin forests from destruction. She climbs a tree to prevent loggers from cutting the oldest tree in the forest. Selena did not eat for twelve hours until a friend, Jammie, took over the observance. Match the correct levels of blood glucose concentration, blood insulin concentration and relative membrane insulin receptor concentration for a skeletal muscle cell 20 hours into Jammie's fast and one hour after Selena had eaten a peanut butter and banana sandwich and a bowl of sweet potato soup.
Plasma Glucose: 90 mg/dl; 125 mg/dl
Plasma Insulin: 10iuU/ml (70 pmol/L); 40iuU/ml (280 pmol/L)
Relative membrane insulin receptor concentration: increasing (high); decreasing (low)
Fasting (Jammie) Satiety (Selena)
Plasma Glucose
Plasma Insulin
Relative Membrane Insulin Receptor Levels
Testname: UNTITLED26
1) E
2) A
3) B
4) D
5) D
6) A
7) C
8) A
9) D
10) A
11) E
12) E
13) C
14) A
15) A
16) A
17) B
18) C
19) F
20) D
21) E
22) F
23) A
24) B
25) E
26) C
27) D
28) endocrinology
29) half-life
30) portal system
31) neurohypophysis
32) adenophyophysis
33) gonadotropins
34) Down-regulation
35) adrenal
36) adrenal cortex
37) adrenal medulla
38) aldosterone, cortisol
39) synergistic
40) permissive
41) antagonists or functional antagonists
42) atrophy
43) trophic hormone
44) hypothalamus
45) hypothalamic-hypophyseal portal system
46) Primary
47) secondary pathology
48) neurohormones
49) C
50) A
51) A
52) B
53) E
54) B
55) cell receptors, signal transduction pathways
56) pheromone or ectohormone
57) ectohormone or pheromone
58) 1. Remove the suspected gland, and observe the animal.
2. Restore the gland or administer a gland extract, and observe the animal.
3. Add a gland or gland extract to a normal animal, and observe the animal for excessive response.
4. Purify gland extracts and isolate the substance. There are many hormones that are secreted from cells that are not par discrete gland and therefore not removable without causing problems beyond loss of the hormone.
59) Second messenger systems activated by peptide hormones modify existing proteins or activate gene transcription to synthesize new proteins. Steroid hormones activate gene transcription to synthesize new proteins, and like peptide hormones, some steroids have nongenomic responses.
60) Synergism, permissiveness, and antagonism. An example of synergism is epinephrine's ability to potentiate the effects of glucagon in elevating blood glucose levels. Reproductive hormones along with adequate thyroid hormone have a permissive effect on the reproductive system because both are required for normal development. Glucagon and insulin are antagonistic hormones because they have opposing physiological actions on blood glucose levels.
61) Discussed in Chapters 6 and 7. Hormones are chemical messengers that are traditionally defined as being secreted by specialized cells into the blood and transported via the circulatory system to distant cells and tissues. Paracrine and autocrine chemical messengers diffuse only very short distances through interstitial fluid. Cytokines may act both at local and long-distance targets.
62) One benefit of a portal system is that it ensures that the controlling hormones will be delivered directly to the target cells. Secondly, since the hormones go directly to their target cells without first passing through the general circulation they are not diluted. The hypothalamus can control the cells of the pituitary with much smaller amounts of releasing and inhibiting hormones than would be necessary if the hormones had to first go through the circulatory pathway before reaching the pituitary. This is the only endocrine portal system.
63) False. A target tissue's response is dependent upon the exact receptor involved and biochemical responses, as well as a variety of other factors. For example, insulin causes skeletal muscle to increase its rate of transport of glucose into the cell, but in the liver insulin affects the activity of enzymes not directly related to glucose transport.
64) Hormones are degraded by enzymes and eliminated in the urine. This disposal of hormones is essential to the ability to regulate their action and prevent them from being too effective. For example, if insulin were not closely regulated, too much glucose could be removed from the blood, depriving brain cells of their only fuel source and causing brain damage, coma, and/or death.
65) The posterior pituitary is an extension of the brain, specifically of the hypothalamus. This part of the pituitary secretes hormones that are synthesized in the hypothalamus, in response to signals from the hypothalamus. The hormones secreted are neurohormones. The anterior pituitary is an outgrowth from the roof of the mouth that fuses to the posterior pituitary during fetal development. This part of the pituitary is true glandular epithelium, and the secretion of its hormones is regulated by releasing and inhibiting hormones secreted by the hypothalamus. In either case, then, the types of hormones and the regulation of their secretion is predictable based on the type of tissue involved.
66) Hormone structure and function in some cases have changed little from primitive vertebrates through mammals. Evidence for this includes the similar response in humans to injected hormones from nonhuman sources. An example of the importance of this relationship is provided by the hormone insulin, which, from extracts of cow, pig, or sheep pancreas, successfully treated diabetes mellitus in humans. Prior to that, diagnosis of diabetes mellitus was followed shortly by death.
67) Corticotropin-releasing hormone, decrease Adrenocorticotrophic hormone, decrease Cortisol, increase This type of relationship is called long-loop negative feedback.
68) Dexamethasone suppresses the pituitary's activity, the secretion of ACTH, which then allowed Anika's level to decline. Since Maria's level did not decline, this shows that the hypersecretion is NOT due to ACTH, thus it must be coming from the adrenal gland. This is the definition of a primary hypersecretion–an elevated amount from the last gland in the reflex pathway.
69) 1. The anterior pituitary is an endocrine gland; it does not release neurohormones because its cells are not neurons. 2. The word trophic is used incorrectly; the term refers to a hormone that causes another gland to release hormone. 3. Anterior pituitary hormones are in fact stimulated by releasing hormones from the hypothalamus.
70) Hypothyroidism results when the thyroid gland produces lower than normal amounts of thyroid hormones. The physician could order blood tests to determine the levels of T3, T4, and TSH in the blood. If the condition is due to disease of the thyroid gland, you would expect to see elevated levels of TSH because of a lack of feedback inhibition by thyroid hormones. If, on the other hand, the problem is due to problems at the level of the hypothalamus or pituitary, you would expect to see decreased levels of TSH.
71) Testosterone is produced by adrenal glands and testes. The presence of elevated testosterone combined with absence of a uterus suggests that she has testes rather than ovaries. The lack of masculinization indicates that her tissues do not respond to the testosterone that is present. There is no uterus because she is genetically male. This can be confirmed by examining her chromosomes. Such individuals have "androgen insensitivity syndrome."
72) Her goal is not realistic. If Xia avoids eating animal products, she can easily eliminate cholesterol from her diet. She cannot, however, eliminate cholesterol from her blood because it is produced by her own liver. Furthermore, such a goal is incompatible with life, as cholesterol is a structural component of cell membranes. Cholesterol is also the precursor to the steroid hormones, which are essential for normal health.
73) The condition is hypothyroidism. Thyroid-stimulating hormone and thyroid-releasing hormone likely also decrease. Decreased responsiveness to injected releasing hormone may indicate a loss of hormone receptors in the anterior pituitary. Increased responsiveness to injected thyroid hormone may indicate up-regulation of hormone receptors in the target tissues, or it may indicate decreased metabolism of the circulating hormone.
74) Diabetes mellitus can result from lack of insulin secretion or from lack of response of insulin receptors. Diabetes insipidus can result from lack of ADH secretion or lack of responsiveness of ADH receptors.
75) 1. 1 receptor/1 mm2 × 104 mm2/cell = 104 receptors per cell.
2. 104 mm2/cell × 106 phospholipids/mm2 = 1010 phospholipid molecules per cell.
3. (1010 phospholipids/cell) / (104 receptors/cell) = 106 phospholipid molecules per insulin receptor.
4. Hormones exert their effects at very low concentrations (therefore it is not surprising that the hormone receptors, thro which the hormones act, are also in low concentration).
76)
Fasting (Jammie) Satiety (Selena)
Plasma Glucose 90 mg/dl 125 mg/dl
Plasma Insulin
10iuU/ml (70 pmol/L); 40iuU/ml (280 pmol/L)
Relative Membrane Insulin Receptor Levels increasing (high) decreasing (low)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) The portions of a neuron that extend off of the roughly spherical cell body are usually collectively called
A) projections. B) prostheses. C) processes. D) protrusions.
2) Neurotransmitter is stored and released from
A) axon varicosities only.
B) axon terminals only.
C) dendritic spines only.
D) cell bodies only.
E) axon terminals and axon varicosities.
3) Information coming into the central nervous system is transmitted along neurons.
A) sensory
B) afferent
C) efferent
D) afferent and sensory
E) sensory and efferent
4) The afferent and efferent neurons together form the
A) peripheral nervous system.
B) autonomic division.
C) visceral nervous system.
D) central nervous system.
E) somatic motor division.
5) The brain and spinal cord together compose the
A) central nervous system.
B) somatic motor division.
C) peripheral nervous system.
D) visceral nervous system.
E) autonomic division.
6) Exocrine glands, smooth muscles, and cardiac muscles are controlled by the
A) peripheral nervous system.
B) autonomic division.
C) somatic motor division.
D) central nervous system.
E) enteric nervous system.
7) Autonomic motor neurons are subdivided into the
A) sympathetic and parasympathetic braches.
B) somatic and enteric branches.
C) central and peripheral branches.
D) visceral and somatic branches.
E) visceral and enteric branches.
8) The enteric nervous system is a network of neurons that function in controlling A) excretion, particularly urination.
B) the skeletal system.
C) digestion.
D) reproduction.
E) the endocrine system.
9) In general, the nervous system is made up of which two types of cells?
1. motor
2. neurons
3. sensory
4. glia
5. associative
A) 2 and 4 B) 1 and 3 C) 3 and 5 D) 1 and 2 E) 3 and 4
10) The cell body of neurons is about
A) 10% of the cell volume.
B) 90% of the cell volume.
C) 50% of the cell volume.
D) found in the same position on every neuron. 10)
11) Interneurons are found
A) only in the brain.
B) throughout the nervous system.
C) in the CNS.
D) only in spinal nerves.
E) only in the spinal cord.
12) The multiple thin, branched structures on some neurons whose main function is to receive incoming signals are the
A) dendrites.
B) cell bodies.
C) soma.
D) axons.
E) None of the answers are correct. 12)
13) The collection of axons that carries information between the central nervous system and the peripheral effectors is called the A) nerve. B) ganglion C) varicosity. D) dendrite. 13)
14) The region where the axon terminal meets its target cell is called the A) collateral.
B) nerve.
C) dendrites.
D) synapse.
E) axon hillock.
15) The axon is connected to the cell body by the
A) synapse.
B) collaterals.
C) axon terminal.
D) axon hillock.
E) myelin sheath.
16) Branches that sometimes occur along the length of an axon are called
A) axon terminals.
B) synapses.
C) axon hillocks.
D) collaterals.
E) dendrites.
17) Neurotransmitters are released from the
A) collaterals.
B) axon terminals.
C) axon hillocks.
D) synapses.
E) dendrites.
18) The term axonal transport refers to
A) the movement of the axon terminal to synapse with a new postsynaptic cell.
B) the release of neurotransmitter molecules from the axon terminal.
C) vesicle transport of proteins and organelles down the axon.
D) the transport of microtubules to the axon for structural support.
E) None of the answers are correct.
19) Anterograde and retrograde axonal transport are forms of transport.
A) slow B) fast C) Neither of these.
20) Clusters of nerve cell bodies in the peripheral nervous system are called A) nodes. B) microglia. C) ganglia. D) neuroglia. E) glia.
21) Glial cells
A) provide structural and metabolic support and help maintain homeostasis of the brain's extracellular fluid.
B) only help maintain homeostasis of the brain's extracellular fluid.
C) only guide neurons during growth and repair.
D) only provide structural and metabolic support.
E) All of the answers are correct.
22) Glial cells communicate primarily using
A) neuromodulators only.
B) chemical signals only.
C) neurohormones only.
D) electrical signals only.
E) electrical signals and chemical signals.
23) Myelin is formed by
A) Schwann cells only.
B) axons only.
C) Schwann cells and oligodendrocytes. D) oligodendrocytes only.
24) These glial cells act as scavengers.
A) microglia
B) astrocytes
C) Schwann cells
D) ependymal cells
E) oligodendrocytes
25) These glial cells may contribute to Lou Gehrig's disease.
A) oligodendrocytes
B) astrocytes
C) ependymal cells
D) Schwann cells
E) microglia
26) The Nernst equation can be used to predict
A) intracellular ion concentrations.
B) the threshold membrane potential.
C) extracellular ion concentrations.
D) the membrane potential resulting from all permeable ions.
E) the membrane potential resulting from permeability to a single ion.
27) Which is the correctly written Nernst equation?
A) 61/z × log [ion]in / [ion]out
C) log 61/z × [ion]in / [ion]out
B) 61/z × log [ion]out / [ion]in
D) log 61/z × [ion]out / [ion]in
28) What does the Goldman-Hodgkin-Katz equation take into account that the Nernst equation does NOT?
A) the sizes of the ions
B) the electrical charges of the ions
C) the permeabilities of the ions
D) the temperature
E) the solubilities of the ions
29) The resting membrane potential results from
A) differences in membrane permeability to ions only.
B) uneven distribution of ions across the cell membrane and differences in membrane permeability to ions.
C) uneven distribution of ions across the cell membrane only.
D) activity of the sodium/potassium pump only.
E) None of the answers are correct. 29)
30) Which ion(s) is/are higher in concentration inside the cell compared to outside?
A) calcium
B) chloride
C) potassium
D) sodium
E) More than one of the answers is correct.
31) The channelopathy known as Q-T syndrome is a result of mutation in channels.
A) sodium
B) calcium
C) chloride
D) potassium
E) sodium, potassium, or calcium
32) Ion channel inactivation is
A) closing of the channel even when the stimulus continues.
B) any type of channel closing.
C) closing of the channel in response to decrease in the stimulus.
D) None of the answers are correct.
33) The total amount of neurotransmitter released at the axon terminal is directly related to the
A) length of the axon.
C) amplitude of the action potential.
B) amplitude of the graded potential.
D) total number of action potentials. 33)
34) Which is the most common location where action potentials start in efferent neurons?
A) cell body
B) dendrites
C) synaptic cleft
D) axon hillock
E) synaptic bouton
35) The rising phase of the action potential is due to
A) K+ flow out of the cell only.
B) K+ flow into the cell only.
C) Na+ flow into the cell only.
D) Na+ flow out of the cell only.
E) Na+ flow out of the cell and K+ flow into the cell. 35)
36) The falling phase of the action potential is due mainly to
A) K+ flow out of the cell only.
B) Na+ flow out of the cell and K+ flow into the cell.
C) Na+ flow in the cell only.
D) K+ flow into the cell only.
E) Na+ flow out of the cell only. 36)
37) The point during an action potential when the inside of the cell has become more positive than the outside is known as the
A) peak.
B) overshoot.
C) depolarization.
D) rising phase.
E) falling phase.
38) Choose the items that are correctly matched.
A) inactivation gate – closed during repolarization
B) inactivation gate – closed at rest
C) activation gate – opens during depolarization
D) activation gate – open at rest
E) All of the answers are incorrectly matched. 38)
39) The absolute refractory period of an action potential
A) ensures one-way travel down an axon, allows a neuron to ignore a second signal sent that closely follows the first, and prevents summation of action potentials.
B) only prevents summation of action potentials.
C) ensures one-way travel down an axon and allows a neuron to ignore a second signal sent that closely follows the first.
D) only allows a neuron to ignore a second signal sent that closely follows the first.
E) only ensures one-way travel down an axon.
40) In order to signal a stronger stimulus, action potentials become
A) higher in amplitude and more frequent.
B) longer-lasting only.
C) higher in amplitude only.
D) higher in amplitude and longer-lasting.
E) more frequent only. 40)
41) All of the following must occur before a second action potential can begin, EXCEPT
A) the Na+ inactivation gate must open and the Na+ activation gate must close.
B) the Na+ and K+ ions that moved in/out of the cell must move back to their original compartments.
C) the absolute refractory period must occur.
D) the Na+ and K+ ions that moved in/out of the cell must move back to their original compartments; the Na+ inactivation gate must open; and the Na+ activation gate must close.
E) None of the answers are correct. 41)
42) Voltage-gated channels are located
A) on the neuron cell body only.
B) within the cytosol only.
C) in the membranes of dendrites only.
D) in the membranes of axons only.
E) in the membranes of dendrites, in the membranes of axons, and on the neuron cell body. 42)
43) The sodium-potassium exchange pump
A) moves sodium and potassium in down their chemical gradients.
B) must re-establish ion concentrations after each action potential.
C) transports sodium ions into the cell during depolarization.
D) transports potassium ions out of the cell during repolarization.
E) requires ATP to function.
44) The all-or-none principle states that
A) all stimuli great enough to bring the membrane to threshold will produce action potentials of identical magnitude.
B) all stimuli will produce identical action potentials.
C) only motor stimuli can activate action potentials.
D) the greater the magnitude of the stimuli, the greater the intensity of the action potential.
E) only sensory stimuli can activate action potentials.
45) When voltage-gated Na+ channels of a resting neuron open,
A) Na+ leaves the neuron and the neuron depolarizes.
B) Na+ enters the neuron.
C) Na+ enters the neuron and the neuron depolarizes.
D) Na+ leaves the neuron.
E) the neuron depolarizes.
46) When voltage-gated K+ channels of a resting neuron open,
A) K+ enters the neuron and the neuron depolarizes.
B) K+ leaves the neuron.
C) K+ leaves the neuron and the neuron depolarizes.
D) K+ enters the neuron.
E) the neuron depolarizes. 46)
47) In the membrane of a resting nerve cell, when chemically gated Cl- channels open,
A) Cl- ions enter the cell.
B) Cl- ions enter the cell and the cell becomes depolarized.
C) the cell becomes depolarized.
D) Cl- ions leave the cell and the cell becomes depolarized.
E) Cl- ions leave the cell.
48) Ion concentrations are first significantly affected after action potential(s).
A) a few dozen
B) a few million
C) a few thousand
D) a few hundred
E) one
49) Action potentials are mainly associated with the membranes of
A) axons only.
B) dendrites only.
C) dendrites and axons.
D) cell bodies only.
E) cell bodies and axons. 49)
50) Which will best increase the conduction rate of action potentials?
A) Decrease the diameter of the axon, decrease the resistance of the axon membrane to ion leakage.
B) Increase the diameter of the axon, increase the resistance of the axon membrane to ion leakage.
C) Decrease the diameter of the axon, increase the resistance of the axon membrane to ion leakage.
D) Increase the diameter of the axon, decrease the resistance of the axon membrane to ion leakage.
51) Which does NOT influence the time necessary for a nerve impulse to be conducted by a neuron?
A) diameter of the axon
B) presence or absence of a myelin sheath
C) whether axon is sensory or motor
D) presence or absence of nodes of Ranvier
E) length of the axon
52) Graded potentials may
A) depolarize the membrane to the threshold voltage.
B) be called EPSPs or IPSPs.
C) hyperpolarize the membrane.
D) initiate an action potential.
E) All of the statements are true.
53) Some neurotoxins work essentially the same way as some local anesthetics, which is to
A) bind to Na+ channels only.
B) bind to Na+ channels and prevent depolarization by blocking Na+ entry into the cell.
C) prevent depolarization by blocking Na+ entry into the cell only.
D) inactivate the enzyme that activates the neurotransmitter and bind to Na+ channels.
E) inactivate the enzyme that activates the neurotransmitter only.
54) The major determinant of the resting potential of all cells is
A) Na+ concentration in the blood and interstitial fluid.
B) Ca2+ concentration in the blood and interstitial fluid.
C) Na+ concentration inside cells.
D) K+ gradient between the blood and interstitial fluid.
E) K+ concentration inside cells.
55) The term hyperkalemia specifically indicates too much potassium in which fluid compartment?
A) interstitial
C) intracellular
55)
B) plasma
D) All of the answers are correct.
56) A chemical synapse ALWAYS includes which of the following?
1. axon terminal
2. presynaptic cell
3. synaptic cleft
4. postsynaptic cell
5. dendrite
A) 2, 3, 4, 5 B) 1, 2, 3, 4 C) 2, 3, 4
1, 2, 3, 4, 5 E) 1, 3, 4 56)
57) Which type of synapse is most common in the nervous system?
A) electrical
B) processing
C) mechanical
D) chemical
E) radiative
58) The ion necessary to initiate the release of acetylcholine into the synaptic cleft is
A) chloride.
B) potassium.
C) calcium.
D) sodium.
E) zinc.
59) To increase the amount of neurotransmitter released onto a postsynaptic cell, the presynaptic cell would have to
A) send action potentials with higher frequency.
B) send action potentials with longer durations.
C) send action potentials with higher voltage (higher amplitude).
D) do nothing; no change is possible since the all-or-none law is in effect.
60) Which is the main inhibitory neurotransmitter in the brain?
A) AMPA receptors
B) glutamate
C) GABA
D) NMDA receptors
E) All of the answers are correct.
61) The inhibitory neurotransmitters of the CNS act by opening channels.
A) only K+
B) only Ca2+
C) Na+ and K+
D) only Na+
E) only Cl61)
62) Excitatory neurotransmitters of the CNS usually act by opening channels.
A) Na+ B) H+ C) K+ D) Cl-
63) Which is NOT a known drug effect on synaptic function?
A) decrease neurotransmitter binding to receptors
B) decrease neurotransmitter synthesis
C) decrease neurotransmitter inactivation
D) change the rate of neurotransmitter release
E) change the type of neurotransmitter found in the synaptic vesicle 63)
64) The site of information integration in the nervous system is the
A) chemical synapse.
B) trigger zone.
C) dendritic membrane.
D) axon terminal.
E) electrical synapse.
65) Once a stimulus binds a receptor on the cell's membrane, what could happen next?
A) The membrane permeability is altered.
B) Ion channels open, allowing ions to enter or exit.
C) A second messenger is activated on the inside of the cell.
D) Any of these actions could happen next.
66) Once the action potential reaches the axon terminal, what happens next?
A) exocytosis of a neurocrine
B) release of a neurohormone into the blood
C) release of a neurotransmitter into the synaptic cleft
D) Any of the above could happen next.
67) Calcium is important in the synapse because it
A) is necessary for acetylcholine synthesis.
B) signals the exocytosis of the neurotransmitter.
C) leaves the axon terminal, hyperpolarizing the cell.
D) binds to receptors on the postsynaptic cell, opening ion channels, and triggering graded potentials.
68) In response to binding a neurotransmitter, a postsynaptic cell can
A) open chemically gated ion channels, causing graded potentials known as fast synaptic potentials and regulate protein synthesis and affect the metabolic activities of the postsynaptic cell.
B) only regulate protein synthesis and affect the metabolic activities of the postsynaptic cell.
C) only close ion channels through G proteins and second messenger systems, producing slow responses.
D) open chemically gated ion channels, causing graded potentials known as fast synaptic potentials, close ion channels through G proteins and second messenger systems, producing slow responses, and regulate protein synthesis and affect the metabolic activities of the postsynaptic cell.
E) only open chemically gated ion channels, causing graded potentials known as fast synaptic potentials.
69) The neurotransmitter thought to be involved in learning and memory is
A) acetylcholine.
B) glycine.
C) glutamate.
D) GABA.
E) norepinephrine.
70) In order for a synapse to be an effective means of cellular communication, removal of neurotransmitter molecules from the synapse is important.
A) True B) False
71) Identify the FALSE statement.
A) The trigger zone is the integrating center of the neuron.
B) EPSPs that reach threshold can initiate an action potential.
C) IPSPs depolarize the membrane.
D) All of the statements are true.
72) An excitatory postsynaptic potential (EPSP)
A) depolarizes a neuron, increasing the likelihood of an action potential.
B) hyperpolarizes a neuron, decreasing the likelihood of an action potential.
C) depolarizes a neuron, decreasing the likelihood of an action potential.
D) hyperpolarizes a neuron, increasing the likelihood of an action potential.
73) Inhibitory postsynaptic potentials (IPSPs)
A) increase membrane permeability to sodium ions.
B) result in depolarizations.
C) decrease potassium ion exit from cells.
D) decrease calcium ion exit from cells.
E) result in hyperpolarizations.
74) When two or more graded potentials arrive at the trigger zone, which of the following could happen?
A) Two excitatory stimuli may be additive, and summation could occur.
B) An excitatory and inhibitory signal can cancel each other out and two excitatory stimuli may be additive, and summation could occur.
C) An excitatory and inhibitory signal can cancel each other out.
D) Two inhibitory stimuli may be additive, resulting in lower excitability.
E) An excitatory and inhibitory signal can cancel each other out; two excitatory stimuli may be additive, and summation could occur; and two inhibitory stimuli may be additive, resulting in lower excitability.
75) Presynaptic facilitation makes a pathway
A) more likely to be in use, just through depolarization of selected neurons and capable of alteration, just through training and conditioning.
B) capable of alteration, just through training and conditioning.
C) more likely to be in use, just through depolarization of selected neurons.
D) less likely to be in use, just through hyperpolarization of selected neurons.
E) less likely to be in use, just through hyperpolarization of selected neurons and capable of alteration, just through training and conditioning.
76) Spatial summation refers to
A) repeated graded potentials reaching the trigger zone one after the other.
B) suprathreshold potentials triggering action potentials that are extra-large.
C) multiple graded potentials arriving at one location.
D) electrical signals reaching neurons from outer space.
75)
E) All of the answers are correct. 76)
77) If a hyperpolarizing graded potential and a depolarizing graded potential of similar magnitudes arrive at the trigger zone at the same time, what is most likely to occur?
A) The cell becomes hyperpolarized.
B) The cell dies.
C) The cell becomes easier to excite.
D) Nothing. They will cancel each other out.
E) An action potential is fired off more quickly than usual.
78) When multiple, possibly even conflicting signals reach a neuron, the neuron evaluates the signals and may respond or not. This property is called
A) EPSPs.
B) temporal summation.
C) spatial summation.
D) graded potentials.
E) postsynaptic integration.
79) When a second EPSP arrives at a single synapse before the effects of the first have disappeared, what occurs?
A) inhibition of the impulse
B) decrease in speed of impulse transmission
C) hyperpolarization
D) temporal summation
E) spatial summation
80) The pattern of synaptic connectivity where a large number of presynaptic neurons provide input to a single postsynaptic neuron, is known as
A) saltatory conduction.
B) divergence.
C) potentiation.
D) integration.
E) convergence.
81) During childhood, growth and development of the brain PRIMARILY occurs by increasing
A) number of dendrites and synapses only.
B) neuron size only.
C) neuron numbers only.
D) neuron numbers and neuron size.
E) neuron size and number of dendrites and synapses.
82) The changing of activity at synapses, which occurs throughout life, is termed
A) synaptic plasticity.
B) senility.
C) synchronicity.
D) elasticity.
E) intelligence.
83) A damaged neuron has a better chance of survival and repair if the is/are undamaged.
A) axon
B) Schwann cells
C) cell body
D) axon and dendrites
E) dendrites
84) Repair of damaged neurons can be assisted by certain neurotrophic factors secreted by the
A) Schwann cells only.
B) cell body only.
C) axon and dendrites.
D) dendrites only.
E) axon only.
85) The tip of an embryonic nerve cell's axon is called a
A) kissing cone.
B) growth cone.
C) growth tip.
D) stem tip.
E) None of the answers are correct.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the glial cell to the nervous system division in which it is found.
86) Schwann cells
87) oligodendrocytes
88) microglia
89) satellite cells
90) ependymal cells
91) astrocytes
A) central nervous system
peripheral nervous system
Match the term with its description (answers may be used more than once).
92) highly branched cells that provide neurons with metabolic substrates
93) specialized immune cells in the CNS
94) cells that form supportive capsules around cell bodies
95) cells that create a selectively permeable epithelial layer to separate fluid compartments of the CNS
96) cells in the CNS that form myelin
97) cells in the PNS that form myelin
98) cells that are a source of neural stem cells
99) cells that myelinate several axons
100) cells that myelinate only one axon each; multiple glial cells per axon
Match the part of the neuron to its description (answers may be used more than once).
101) may be covered with myelin
102) receive most of the incoming synapses
103) occupy the least amount of cell volume
104) make proteins necessary for repair of damaged neuron
105) contribute most to membrane surface area of cell
106) supported by satellite cells
107) where most graded potentials originate
108) location of voltage-gated ion channels involved in action potentials
Match the type of signal to its description (answers may be used more than once).
109) may be hyperpolarizing
110) originate(s) at the trigger zone
111) originate(s) on dendrites and cell bodies
112) can involve chemically gated ion channels
113) require(s) a threshold stimulus to occur
114) size increases if stimulus strength increases
115) can result from influx of sodium
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
116) The gaps between adjacent Schwann cells on an axon are called 116)
117) The potential difference across a membrane or other barrier is a measure of the across the barrier.
118) The sum of all of the electrical and chemical gradients active across the membrane is known as the
119) The two types of electrical signals in neurons are
120) The minimum amount of stimulus required to depolarize an excitable membrane and generate an action potential is known as the .
121) The phenomena states that the properties of the action potential are independent of the relative strength of the depolarizing stimulus.
122) The time during which an excitable membrane cannot respond to further stimulation regardless of the stimulus strength is the 122)
123) The period of time during which an excitable membrane can respond again, but only if the stimulus is greater than the initial stimulus is the 123)
124) At a(n) synapse, a neurotransmitter is released to affect the postsynaptic cell. 124)
125) In a(n) synapse, there is a direct physical connection between cells. 125)
126) A is a compound that influences a postsynaptic cell's response to a neurotransmitter. 126)
127) The addition of stimuli arriving one after another to produce an action potential is called 127)
128) The addition of several stimuli arriving from different locations on the same cell to produce an action potential is called 128)
129) Name the two factors that influence the membrane potential. 129)
Indicate true or false. If FALSE, substitute a word or phrase for the boldfaced word(s) that will make the statement TRUE.
130) Schwann cells are the glial cell associated with myelination the central nervous system 130)
131) The gaps between Schwann cells are called synapses 131)
132) An influx of Na+ ions depolarizes the membrane of an axon. 132)
133) The absolute refractory period is important in one-way direction of action potentials. 133)
134) If the graded potential increases in amplitude, then the frequency of the action potentials 134) fired also increases.
135) In spatial summation the same presynaptic neuron is repeated until a threshold level of depolarization is reached. 135)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
136) Microvilli are present on cells that benefit from an increased membrane surface area for their function. Which structure(s) on a neuron provide a comparable benefit?
A) dendrites
B) collaterals
C) varicosities
D) cell body
E) axon
137) A home satellite dish receives signals from a satellite in outer space, allowing your television to display TV shows. Which part of a neuron is similar to the satellite dish?
A) dendrites
B) axon
C) collaterals
D) cell body
E) varicosities 137)
138) In terms of embryonic origin, neurons are most closely related to cells.
A) cardiac muscle
C) skeletal muscle
B) connective tissue
D) epithelial 138)
139) If the resting axon's membrane becomes more permeable to potassium ions,
A) it will take a stimulus of larger magnitude to initiate an action potential.
B) the inside of the membrane will become more positively charged.
C) the membrane will depolarize more rapidly.
D) the hyperpolarization at the end of the action potential will not occur.
140) If the sodium-potassium pumps in the cell membrane of a neuron fail to function, over time
A) the membrane resting potential will become more positive than normal.
B) the intracellular concentration of sodium ion will increase.
C) the extracellular concentration of potassium ion will increase.
D) All of the answers are correct.
141) How would the absolute refractory period be affected if voltage-gated sodium channels remained inactivated?
A) It would be the same whether the channels remained inactivated or not.
B) It would be shorter than normal.
C) It would be longer than normal.
D) None of the answers are correct.
142) Identify the FALSE statement.
A) Under normal conditions, all action potentials in a given cell are identical.
B) Ions diffuse at nodes of Ranvier.
C) The voltage-gated sodium and potassium channels begin to open during the depolarization.
D) The amplitude of the action potential depends on the amplitude of the graded potential that precedes it.
143) Which statement is true when a neuron is at rest?
A) The inactivation gate is open.
B) No Na+ crosses the membrane.
C) The activation gate is closed.
D) The activation gate is closed and no Na+ crosses the membrane.
E) The activation gate is closed and the inactivation gate is open.
144) In the first phase of initiating an action potential in a neuron, Na+ ions flow in and
A) create a negative feedback loop.
B) create a negative feedback loop and activate the sodium/potassium pump.
C) activate the sodium/potassium pump.
D) create a positive feedback loop.
E) create a positive feedback loop and activate the sodium/potassium pump.
145) What stops the rising phase of the action potential?
A) The Na+ activation gate opens.
B) The Na+ inactivation gate closes.
C) The sodium activation gate closes.
D) The Na+ inactivation gate opens.
E) The K+ gate closes.
146) The inactivation gate
A) quickly opens and closes after depolarization.
B) is coupled to the movement of the activation gate, but is much slower.
C) depends on a loss of Na+ permeability to be triggered.
D) depends on a loss of K+ permeability to be triggered.
E) depends on a change of +100 mV from rest to be signaled to close.
147) During the relative refractory period, an initial threshold-level depolarization is usually not sufficient to initiate an action potential. Why?
A) Only some Na+ channels have returned to their resting position.
B) Only a few K+ channels have returned to their resting position.
C) Some Na+ channels have returned to their resting position and K+ channels are still open, so Na+ entry is offset by K+ loss.
D) Only K+ channels are still open, so Na+ entry is offset by K+ loss.
E) The statement is incorrect; a threshold-level depolarization always triggers an action potential.
148) The following are the main steps in the generation of an action potential:
1. sodium channels are closed
2. more voltage-regulated potassium channels open and potassium moves out of the cell, initiating repolarization
3. sodium channels return to their resting properties
4. a graded depolarization brings depolarization to threshold
5. a temporary hyperpolarization occurs
6. sodium channels open
7. sodium ions enter the cell and further depolarization occurs
The proper sequence of these events is
A) 6, 7, 4, 1, 2, 3, 5.
B) 4, 6, 7, 3, 2, 5, 1.
C) 2, 4, 6, 7, 1, 3, 5.
D) 4, 2, 5, 6, 7, 3, 1.
E) 4, 6, 7, 1, 2, 5, 3.
149) When comparing action potentials to graded potentials, an/two important distinguishing characteristic/s is/are
A) graded potentials can undergo summation.
B) action potentials can undergo summation and the rate of action potentials is limited by the refractory period.
C) action potentials can undergo summation.
D) graded potentials can undergo summation and the rate of action potentials is limited by the refractory period.
E) that the rate of action potentials is limited by the refractory period. 149)
150) When more action potentials arrive at the axon terminal, how are neurotransmitters affected?
A) More molecules are released into the synapse.
B) Fewer molecules are released into the synapse.
C) Different molecules are released into the synapse.
D) There is no effect–all signals are identical. 150)
151) When more action potentials arrive at the axon terminal, how is a postsynaptic neuron affected?
A) Neurotransmitter release does not change, and the postsynaptic neuron behaves the same way it always behaves.
B) Neurotransmitter release increases, but does not change the graded potentials in postsynaptic neurons.
C) Neurotransmitter release increases, increasing the frequency or magnitude of graded potentials in the postsynaptic neuron.
D) Neurotransmitter release does not change, but voltages in the postsynaptic neuron increase.
152) If a stimulating electrode is placed in the middle of a resting axon and an above-threshold voltage is applied to the electrode, action potentials
A) will start at that point and travel in both directions in the axon.
B) will start at that point and travel only toward the cell body.
C) will start at that point and travel only toward the axon terminal.
D) will not occur.
153) Conduction occurs along an axon because
A) entry of Na+ stimulates the adjacent channels to open.
B) once Na+ enters the cell, the entire membrane depolarizes simultaneously.
C) axonal transport "walks" voltage changes along the membrane.
D) exit of K+ stimulates the adjacent channels to open.
154) Conduction speed can be increased by
A) increasing the length of a neuron.
C) removing myelin.
B) increasing the diameter of a neuron.
D) All of the above. 154)
155) When sodium channels open during an action potential, the opening is caused by
A) presence of positive charge.
C) binding of sodium ions.
156) The primary problem in hyperkalemia is that
155)
B) binding of potassium ions.
D) presence of calcium.
A) neurons are harder to excite because their resting potential is hyperpolarized.
B) neurons are easier to excite because their resting potential is closer to threshold and neurons respond too quickly to smaller graded potentials.
C) neurons are easier to excite because their resting potential is closer to threshold.
D) neurons respond too quickly to smaller graded potentials.
E) neurons are harder to excite because their resting potential is hyperpolarized and neurons respond too quickly to smaller graded potentials.
157) Graded potentials can
A) only act as signals over short distances.
B) act as signals over long distances and make an action potential more or less likely.
C) act as signals over short distances and make an action potential more or less likely.
D) only act as signals over long distances.
156)
E) only make an action potential more or less likely. 157)
158) The following are steps involved in transmission at the cholinergic synapse:
1. Chemically gated ion channels on the postsynaptic membrane are opened.
2. Calcium ions enter the axon terminal.
3. An action potential depolarizes the axon terminal at the presynaptic membrane.
4. Acetylcholine is released from storage vesicles by exocytosis.
5. Acetylcholine binds to receptors on the postsynaptic membrane.
The correct sequence for these events is
A) 2, 4, 1, 3, 5.
B) 1, 2, 3, 4, 5.
C) 3, 2, 4, 5, 1.
D) 4, 2, 1, 5, 3.
E) 2, 5, 4, 1, 3.
159) Arrange the following events in the proper sequence:
1. Efferent neuron graded potential reaches threshold and fires an action potential.
2. Afferent neuron graded potential reaches threshold and fires an action potential.
3. Target organ responds.
4. CNS reaches decision about response.
5. Sensory receptor detects change in the environment.
A) 5, 1, 4, 2, 3 B) 3, 1, 4, 2, 5 C) 5, 3, 4, 2, 1 D) 5, 2, 4, 1, 3 E) 2, 3, 5, 1, 4
160) How would blocking retrograde transport in an axon affect the activity of a neuron?
A) The cell body would not be able to transport products to the axon terminals.
B) The cell body would not be able to respond to changes in the distal end of the axon.
C) The neuron would not be able to produce action potentials.
D) The neuron would be unable to depolarize when stimulated.
E) The neuron would not be able to produce neurotransmitters.
161) The basis of integration of neural information is
A) spontaneous activity in pacemaker neurons.
B) the area under the curve of postsynaptic potentials overlapping in time and space.
C) addition of postsynaptic potentials overlapping in time and space.
D) command signals from central pattern generators.
162) Caffeine, nicotine, and alcohol all have effects on
A) action potential conduction.
B) neurotransmitter reuptake.
C) long-term potentiation.
D) neurotransmitter degradation.
E) synaptic activity.
163) Tsering's father suffers a stroke that leaves him partially paralyzed on his right side. What type of glial cell would you expect to find in increased numbers in the damaged area of the brain that is affected by the stroke?
A) microglia
C) oligodendrocytes
160)
161)
162)
163)
B) Schwann cells
D) astrocytes
164) Tetrodotoxin is a toxin that blocks voltage-gated sodium channels. What effect does this substance have on the function of neurons?
A) Action potentials lack a repolarization phase.
B) The absolute refractory period is shorter than normal.
C) The toxin does not interfere with neuron function because the voltage-regulated sodium channels would still function.
D) The neuron is not able to transmit action potentials.
E) Neurons depolarize more rapidly.
165) Inhibition of neural activity can result from
A) presynaptic events only.
B) presynaptic events and postsynaptic events.
C) postsynaptic events only.
166) Which of the following is a possible mechanism for presynaptic facilitation?
A) extracellular concentration of sodium increases.
B) extracellular concentration of potassium increases.
C) temporal summation occurs.
D) calcium channels in the presynaptic membrane are inhibited.
E) calcium channels in the presynaptic membrane remain open longer.
167) Learning and memory are thought to be due to synaptic changes known as
A) excitation.
B) inhibition.
C) long-term potentiation.
D) facilitation.
E) modulation.
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
168) Products from the cell body of a neuron are transported to the axon terminals by . 168)
169) A change in the conditions in the axon terminal can cause a change in the environment of the cell body as a result of . 169)
170) Graded potentials that increase the likelihood of an action potential bring the closer to threshold. 170)
171) Graded potentials that arrive at postsynaptic neurons are called if they make that cell more likely to fire an action potential. 171)
172) Graded potentials that arrive at postsynaptic neurons are called if they make that cell less likely to fire an action potential. 172)
173) For to occur, a second potential must arrive before a previous one has been completed. 173)
174) When two or more graded potentials arrive at the trigger zone within a short period of time, their effects are additive and occurs. 174)
175) Receptors that work through second messenger systems are called receptors. 175)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
176) Briefly explain the organization of the nervous system in either paragraph form or using a concept map. Be sure to discuss the central, peripheral, and enteric nervous system and the divisions and branches discussed in the text.
177) Draw a motor neuron, being sure to include and label the following parts: axon(s), dendrite(s), cell body, axon collateral(s), axon terminal(s), myelin sheath, and other parts.
178) Why are mitochondria necessary at axon terminals?
179) Why is it necessary for fast axonal transport to go both forward and backward?
180) Compare and contrast action and graded potentials. Your answer should include a definition of each, types, characteristics, ionic basis, functions, and anything else necessary to answer the question.
181) Compare and contrast fast and slow synaptic potentials, including mechanisms used and what kinds of cells they occur in.
182) How does the function of dendritic spines in the CNS differ from dendrites in the PNS?
183) Compare and contrast Schwann cells and oligodendrocytes.
184) Write out the Nernst and GHK equations, and explain the significance of each. Define equilibrium potential.
185) What is a channelopathy, and what are some examples?
186) What causes a graded potential to degrade?
187) Name two ways a cell changes its membrane permeability to ions. (Hint: One way is relatively slow.)
188) If both Na+ and K+ channels are opened by depolarization, why do we see more Na+ flux during the rising phase of an action potential?
189) What is the trigger zone? Where is the trigger zone found in efferent, afferent, and interneurons? Do the terms trigger zone and axon hillock have the same meaning? Explain.
190) "A refractory period occurs following all types of potentials." Is this statement TRUE or FALSE? What structures are refractory? Why or why not?
191) Consider the statement "all action potentials are identical to one another." However, there is an exception where an action potential can have a smaller than normal amplitude. When does this occur and how?
192) Explain the kiss-and-run model of synaptic vesicle exocytosis, and how it differs from the classic model.
193) Discuss the membrane permeabilities of major ions and how they contribute to the overall resting membrane potential of neurons.
194) If potassium channels in a neuron were blocked, would it be possible to produce an action potential? If so, describe the probable appearance of these parts of a graph: threshold, rising phase, peak, falling phase, undershoot. If not, explain.
195) Explain why the voltage-gated Na+ channels can close while the cell is depolarized even though the depolarization was the initial stimulus for the channel opening. Include a discussion on refractory periods and explain why action potentials travel in only one direction.
196) Explain the two reasons why graded potentials lose strength as they move through the cell. Why don't action potentials lose strength?
197) Compare and contrast the EPSP, IPSP, and action potential including ions involved, all-or-none phenomenon, specific cellular locations, and specific cell types involved.
198) Define temporal and spatial summation Where does the summation occur? Can they occur at the same time in a typical multipolar neuron? What key property of neurons do these forms of summation demonstrate?
199) Your study partner has concluded that a single action potential, once initiated, spreads down the length of an axon, without decreasing in strength; similarly, a single graded potential spreads down the length of a dendrite, but decreases with distance. Is she completely correct? Explain. How can the mechanism of decremental and non-decremental conduction help her sort this out? How is the process different in myelinated vs. unmyelinated neurons? How may the dominoes analogy help her to understand signal propagation?
200) Polio is an uncommon disease in most developed countries, but it was very common before widespread use of the polio vaccine. Polio is caused by a virus that infects and destroys somatic motor neurons. From this information, would you expect a person with polio to lose sensation, motor control, other organ function, and/or cognitive function? Explain. While most victims of polio survive, some do not. What is the most likely cause of death?
201) In a laboratory situation, a nerve can be stimulated by applying voltage from a stimulator. If a stimulus was applied in the middle of a nerve roughly halfway between the cell bodies and the axon terminals, would resulting action potentials travel only from the stimulus point to the axon terminal? Why or why not? How is this similar to or different from the basic characteristics of an action potential discussed in this chapter? What does this tell you about the nature of the axon?
202) A scientist discovers a toxin in the venom of a poisonous marine invertebrate. Tests on lab mammals show that this toxin prevents sodium channel inactivation. How would this affect the action potentials produced in the neurons of a poisoned mammal?
203) Your study partner in your physiology class insists that axons conduct graded potentials, and that they play a vital role in initiating the action potential. Do you agree or disagree? Defend your answer.
204) A compound action potential is recorded using electrodes on a nerve. How does a nerve differ from an axon? Amplitude and duration of a compound action potential vary according to the stimulus intensity applied to the nerve. Given that there is no such variation in the action potential of a single axon, how can you explain this?
205) Explain the processes that lead to the exocytosis of neurotransmitter from a presynaptic cell. Which parts are recycled? Which ion initiates exocytosis?
206) How do the following relate to nervous system development and/or healing? Synaptic plasticity, neuroglia, neurotrophic factors.
207) In multiple sclerosis, there is progressive and intermittent damage to the myelin sheath of central axons. One symptom is poor motor control of the affected area. Why does destruction of the myelin sheath affect motor control?
208) Multiple sclerosis (MS) is one of the better studied diseases resulting from demyelination of axons (in MS, only CNS axons are affected). Some of the earliest symptoms of the disease are difficulty in focusing the eyes, such as in reading, and difficulty in maintaining balance, and frequently not being able to make adjustments in posture to avoid falling. How do these symptoms "fit" with what you know about nerve impulses, myelin sheaths, and the location of gated ion channels in the membranes of axons?
209) What factors determine the maximum frequency of action potentials conducted by an axon?
210) Compare and contrast the communication mechanisms between the nervous and endocrine systems. In other words, how do neurons and neurotransmitters signal to their postsynaptic cells, compared to the way endocrine glands and hormones communicate with their target cells?
211) You and your lab partner have prepared a frog nerve for gathering data on action potentials. You connect an electronic stimulator to the nerve and ask your partner to gradually increase the voltage until you see an action potential. Your partner says that the voltage knob is stuck and will not increase the voltage. Is there another way to initiate action potentials using this stimulator? If so, what do you tell your partner to do?
212) A lab technician has accidentally added lithium instead of sodium in a solution of saline for use by students in neurophysiology labs. If a frog nerve was bathed in this solution, what would happen upon stimulation of the nerve?
213) Explain the differences in axon regeneration in the CNS and PNS, and how this affects recovery from injury. What experiments might scientists try based on these differences?
214) Create diagrams (of the cells) and graphs (of the potentials) to illustrate the two different situations described below in a multipolar neuron with a threshold voltage of 15 mV above resting potential. In each, show loss of strength of graded potentials (by drawing the same graded potential at different points as it spreads along the neuron), as well as summation.
Situation 1: There are three simultaneously active synapses on the multipolar neuron, two producing EPSPs and IPSP. At least one of the EPSPs is larger than 15 mV at the synapse. The neuron does NOT generate an action pot
Situation 2: There are two simultaneously active synapses, one producing an EPSP and the other an IPSP. The ne generates an action potential.
215) Let's say we have finally discovered life on Venus. Scientists are investigating a newly discovered life form: a single-celled organism found in the swampy canals. You have been contracted to perform an electrophysiology study. Using intracellular electrodes to measure the electrical charge inside the cell, you find it has a resting membrane potential of -45 mV when the outside fluid is set to 0 mV. Additionally, you have determined ion concentrations and listed them below.
You have used new molecular biology techniques to insert protein channels into the cell membrane that allow on and Cl- to pass. Predict which ion(s) will move, what direction it (they) will move, and what force(s) is/are acting on it (them).
216) Use the Nernst equation to predict the membrane potential for each ion.
217) If an axon has an absolute refractory period of 2 msec, what is the maximum frequency of action potential (AP) production in that neuron?
218) Draw and label a graph of an action potential in a neuron.
219) Draw a graph showing change in membrane permeability (do not worry about including the units of permeability) to sodium and potassium during the course of an action potential. For reference, superimpose a graph of the action potential.
220) Draw a graph showing what would happen to resting membrane potential over time, if the sodium/potassium pumps were not functioning. How would this affect a neuron's ability to produce action potentials? What does this imply about the quantity of ions that normally cross the membrane during the course of an action potential?
221) The amplitude of an action potential depends in part on the amount of sodium in the extracellular fluid. Rama has carefully placed an intracellular electrode in a neuron. He tests the role of extracellular sodium by changing the concentration in the fluid outside of the neuron and recording an action potential after each change. The data he generated are shown in the table, where amplitude listed is the peak amplitude of the action potential; make an appropriate graph.
222) Draw graphs showing the effects of hypokalemia and hyperkalemia on action potential production. Don't worry about exact millivolt values – the point is to show that you understand the effects of these conditions relative to normal.
223) In the graphs below, identify normal plasma potassium, hyperkalemia, and hypokalemia.
224) Draw graphs showing the effect on action potentials in a cell following effective doses of each of the listed neurotoxins. Assume that the cell is normally brought to threshold by an electrical stimulus applied to it, so that any abnormality is due to the toxin. Precise values for voltage and duration are not important, just a general trend in how the action potential may be different from normal.
1. puffer fish poison (inhibits voltage-gated sodium channels)
2. tetraethylammonium (inhibits voltage-gated potassium channels)
3. ouabain (inhibits sodium-potassium pumps)
4. sea anemone toxin (inhibits voltage-gated sodium channel inactivation)
225) Draw graphs showing the effects on action potentials in a postsynaptic cell of effective doses for each of the liste Assume that the cell is normally brought to threshold by the stimuli applied to its inputs, so that any abnormalit to the toxin.
1. curare (prevents receptor from binding neurotransmitter)
2. botulinum toxin (prevents neurotransmitter release)
226) Explain the roles that the AMPA and NMDA receptors play in long-term potentiation.
Answer Key
Testname: UNTITLED27
1) C
2) E
3) D
4) A
5) A
6) B
7) A
8) C
9) A
10) A
11) C
12) A
13) A
14) D 15) D
16) D
17) B
18) C
19) B
20) C
21) E
22) B
23) C
24) A
25) E
26) E
27) B
28) C
29) B
30) C
31) E
32) A
33) D
34) D
35) C
36) A
37) B
38) C
39) A
40) E
41) B
42) E
43) E
44) A
45) C
46) B
47) A
48) C
49) A
50) B
Answer Key
Testname: UNTITLED27
51) C
52) E
53) B
54) D
55) B
56) B
57) D
58) C
59) A
60) D
61) E
62) A 63) E
64) B 65) D
66) D
67) B
68) D 69) C
70) B 71) C
72) A
73) E
74) E
75) A 76) C
77) D
78) E
79) D
80) E
81) E
82) A 83) C
84) A 85) B
86) B
87) A
88) A
89) B
90) A
91) A
92) A
93) B 94) D
95) C 96) E
97) F 98) C
99) E
100) F
Answer Key
Testname: UNTITLED27
101) A
102) C
103) B
104) B
105) C
106) B
107) C
108) A
109) C
110) A
111) C
112) C
113) A
114) C
115) B
116) nodes of Ranvier
117) voltage
118) driving force
119) graded potentials and action potentials
120) threshold
121) all-or-none
122) absolute refractory period
123) relative refractory period
124) chemical
125) electrical
126) neuromodulator
127) temporal summation
128) spatial summation
129) 1. the concentration gradients of ions across the membrane 2. the membrane permeability to those ions
130) False, peripheral nervous system
131) False, nodes of Ranvier
132) True
133) True
134) True
135) False, temporal summation
136) A
137) A
138) D
139) A
140) D
141) C
142) D
143) E
144) D
145) B
146) B
147) C
148) E
149) D
150) A
151) C
152) A
153) A
154) D
155) A
156) B
157) C
158) C
159) D
160) B
161) C
162) E
163) A
164) D
165) B
166) E
167) C
168) anterograde transport
169) retrograde transport
170) membrane potential
171) excitatory
172) inhibitory
173) summation
174) temporal summation
175) metabotropic
176) Answers will vary. There are three divisions: the central nervous system (CNS), the peripheral nervous system (PNS), and the enteric nervous system. The CNS consists of the brain and spinal cord and acts as the integrating center for neural reflexes. The brain is also where thoughts and consciousness are formed. The PNS includes the afferent branch, which monitors the internal and external environment and sends signals to the CNS, and the efferent branch, which carries signals from the CNS to effector cells throughout the body. Within the efferent branch, there is the somatic motor division, which controls skeletal muscle, and the autonomic division. The autonomic division, or visceral nervous system, controls the smooth and cardiac muscles and exo- and endocrine glands. It is further divided into the sympathetic and parasympathetic branches.
177) See Figure 8.2 in the chapter
178) Energy is required metabolism and transport.
179) The organelles and cellular components transported to the axon terminal must also be returned to the cell body for recycling. Fast retrograde recycling may also be used for nerve growth factor transport to the cell body.
180) Action potentials are stereotyped changes in axon membrane potential that function in long-distance communication between neurons and their target cells. Graded potentials are variable membrane potential changes, usually in dendrites of multipolar neurons, that function in either short-distance communication or changing the probability of an action potential.
Action potentials result from opening of voltage-regulated ion channels, which occurs at or above a threshold voltage. potentials are not regenerative and result from the opening of ion channels in response to neurotransmitter or a specific stimulus such as sound or odor, in the case of sensory receptors
The rising phase results from influx of sodium, and the falling phase from efflux of potassium. Other characteristics incl after-hyperpolarization, all-or-none nature, conduction without decrement, independence of amplitude and duration from stimulus strength, refractory period, faster velocity in larger diameter or in myelinated axons. Graded potentials can be depolarizing, if the ion channel is a sodium channel, or hyperpolarizing in the case of potassium or chloride channels. Depolarizations increase the probability that threshold voltage will be attained and an action potential will result. Hyperpolarizations decrease the probability of a resulting action potential. Amplitude and duration are proportional to stimulus intensity, and graded potentials are conducted with decrement.
181) Fast synaptic potentials begin quickly and last only a few milliseconds; this category includes EPSPs and IPSPs. Slow synaptic potentials take longer to begin and last longer commonly involve G-protein coupled receptors; this type of response is important in growth, development, and long-term memory.
182) Dendritic spines have polyribosomes to make their own proteins, send signals to other neurons, and are involved in learning, memory, and various pathologies. PNS dendrites receive external information and transfer it within the neuron.
183) Both insulate axons by creating myelin. Schwann cells, found in the PNS, are associated with a single axon. One axon may have many Schwann cells wrapped around it leaving small gaps of unmyelinated areas called nodes of Ranvier. Oligodendrocytes are found in the CNS and form myelin around portions of several axons.
184) This is discussed in the "8.3 Electrical Signals in Neurons" section of the chapter. The Nernst equation is used to calculate the equilibrium potential for individual ions, while the GHK equation calculates the predicted resting membrane potential of a cell. The equilibrium potential is the voltage at which there is no net movement of a particular ion across the membrane, because the force of the concentration gradient is exactly balanced by the force of the electrical gradient.
185) See the first "Clinical Focus" box in the chapter.
186) Current leakage across the membrane and resistance of the cytoplasm are two factors.
187) 1. opens or closes existing channels
2. inserts or removes membrane channels
188) Although both channels are opened by depolarization, the Na+ channels open quickly allowing rapid Na+ entry into the cell. The peak of Na+ permeability coincides with the peak of the action potential, while the K+ channels open more slowly and don't reach their peak ion permeability until the falling phase of the action potential.
189) The trigger zone is an area of the neuron that contains a high membrane concentration of voltage-gated Na+ channels and is near an area that lacks these. In order for action potentials to occur, graded potentials reaching the trigger zone must depolarize the membrane to the threshold voltage. In efferent and interneurons, the trigger zone is the axon hillock (also called the initial segment). In afferent neurons, the trigger zone is located where the dendrites join the axon (immediately adjacent to the receptor), rather than at the axon hillock. The axon hillock is an anatomical region, whereas the trigger zone is defined by its function rather than its location.
190) False. The refractory period occurs after action potentials and is a distinguishing characteristic, and results from properties of the voltage-gated sodium channels. Graded potentials do not involve channels that have refractory periods. Two stimuli that reach a dendrite at nearly the same time will increase the graded potential produced, whereas if two suprathreshold depolarizations reach the trigger zone at nearly the same time, the first will cause an action potential and the second will be ignored, because of the refractory period.
191) During the relative refractory period, a smaller than normal action potential can occur. During this period potassium channels are still open causing repolarization. If a wave of depolarization occurs, Na+ can enter the cells through the newly reopened Na+ channels, but this depolarization is offset by the K+ efflux.
192) With the kiss-and-run model the synaptic vesicles fuse to the presynaptic membrane at a fusion complex. When the neurotransmitter is released through the fusion complex into the synaptic cleft the vesicles then pull away from the complex and re-enter the vesicle pool in the cytoplasm. With the classical model the vesicle becomes incorporated into or becomes part of the cell membrane.
193) The average resting membrane potential is -70 mV. It is primarily determined by the concentration gradient of K+ and the membrane permeabilities of K+ , Na+ , and Cl- The equilibrium potential for K+ predicted by the Nernst equation is -90 mV. The resting membrane potential is more permeable to K than Na. However, because the cell's resting potential is more positive than -90mV there must be another contributing ion, and it is the Na+ leak channels that allow positive Na+ ions into the cell which cause the resting potential to be slightly more positive.
194) Assuming sodium channels are functioning normally, there would still be an action potential. Threshold would be unaffected, because it is a property of sodium channels. A peak voltage will be reached when the sodium channels become inactivated; this voltage may be higher than normal since usually there is a partial canceling of the rising voltage as potassium exits. Without a potassium current, the falling phase would be much slower, being dependent on the sodium-potassium pump removing the sodium ions that came in. The undershoot would be absent because it is a result of potassium current.
195) The channels have two gates: activation and inactivation gates. (See Fig. 8.10.) At rest, the activation gate is closed and the inactivation gate is open. Upon depolarization both gates move: the activation gate opens allowing Na+ to enter the cell and the inactivation gate (with a delay of 0.5 msec) closes stopping the influx of Na+ At this point during the action potential, the peak has been reached and repolarization occurs due to the K+ ions leavin cell. During this time, even if another wave of depolarization occurred, the Na+ channels cannot be opened because the activation gate is already open and the inactivation gate is closed. This is the absolute refractory period, when another action potential absolutely cannot occur because the Na+ channels have not reset to their original positions. The relative refractory period occurs after some of the Na+ channels have reset, but a higher than normal depolarizing grad potential is necessary to cause another action potential. Refractory periods also explain why action potentials cannot move backward. (See Fig. 8.15.) The part of the axon exper the action potential has open Na+ channels. An increase in Na+ inside the cell causes depolarization and perpetuates th action potential toward the axon terminal due to local current flow. The area of the axon toward the trigger zone, where the action potential (AP) occurred a moment earlier, is in the absolute refractory period and will not experience another action potential even with a depolarization.
196) As a depolarization wave moves through the cell, some of the positive charge is lost to the extracellular fluid through leak channels. Additionally there is cytoplasmic resistance. Action potentials do not lose strength because they are regenerated in each patch of membrane.
197) EPSPs and IPSPs are graded potentials in postsynaptic cells resulting from the action of neurotransmitters at synapses, which are usually on dendrites of multipolar neurons, but could also be on the synaptic region of any target cell. EPSPs increase the probability that a postsynaptic action potential will result, because they involve an influx of sodium, which depolarizes the membrane potential, bringing it closer to threshold. IPSPs decrease the probability that a postsyn action potential will result, because they involve either an influx of chloride or an efflux of potassium, either of which hyperpolarizes the membrane potential, moving it farther from threshold. Action potentials occur in axons of neurons, or in muscle cell membranes. They may result from PSPs or in the case of s neurons, specific stimuli such as sound or odor, which cause a type of graded potential called a receptor potential. Action potentials begin when graded potentials depolarize the membrane potential to threshold. The rising phase of an action potential results from sodium influx, and the falling phase from potassium efflux. Action potentials, but not graded potentials, are an all-or-none phenomenon.
198) See Figs. 8.24 and 8.25 in the chapter. Temporal summation is the addition of graded potentials that overlap in time; that is, a second potential arrives before the first one from that source has finished. Spatial summation occurs when there is simultaneous arrival of graded potentials originating from more than one synaptic input. Summation occurs at the trigger zone. Typically a multipolar neuron has many active synapses at a given time, with multiple potentials being produced at each. Summation demonstrates postsynaptic integration.
199) While she is correct about graded potentials, she is incorrect about action potentials. A GP is initiated at a synapse, for example, and spreads in all directions but loses strength as the ions diffuse; no additional ions are crossing the membrane to boost this signal. An AP is initiated at a trigger zone, then a second, identical AP is triggered in the next patch of membrane as more ions enter the cell; thus, there was no decrement of the AP. Between membrane patches, the signal is decremental for the same reasons that GPs decrease with spread, but sufficient to stimulate the next AP. In myelinated axons, the subsequent APs are farther apart than in unmyelinated axons. A row of dominoes, if spaced appropriately, can be felled by pushing on just the first one. That domino falls and does not spread to the end of the row, but it causes its neighboring, identical domino to fall, and so on.
200) If only somatic motor neurons are affected, the primary result should be paralysis or inability to control skeletal muscles. Because respiration involves skeletal muscles, some victims die of suffocation.
201) Action potentials would travel in both directions from the stimulus point, simultaneously toward the cell bodies and toward the axon terminals. This is because the axon segments on each side of the stimulus point are presumably not refractory when the stimulus is delivered, thus there is nothing to prevent the action potentials from traveling in both directions. In normal transmission, the action potential begins where the axon starts, and travels only away from that point, not toward, because the membrane becomes refractory for a period of time after the action potential occurs. Thus, the axon is quite capable of transmitting action potentials in either direction, even though normally it is prevented from doing so.
202) Without sodium channel inactivation, the action potential would not repolarize as quickly, thus any function dependent upon the action potential would be prolonged, including neurotransmitter release and postsynaptic response. Also, the refractory period would not exist, thus action potentials would travel back up the axon, and down again, repeatedly.
203) Your study partner is correct. This is easiest to explain in the context of the myelinated axon. Voltage-regulated ion channels, which produce the action potential, are located only at nodes of Ranvier. This means that the intervening regions do not generate action potentials. After an action potential is produced at one node, the ions diffuse from this node to the next in a decremental manner, but produce sufficient depolarization at the next node to produce an action potential there.
204) A nerve consists of many axons. A regular action potential is produced by a single axon, whereas a compound action potential is recorded by equipment from a nerve when multiple axons are producing action potentials, and the voltages add together. Increasing stimulus intensity increases the number of axons contributing to the compound action potential. This is because different axons have different threshold voltages, so increasing the voltage stimulates a larger number of axons.
205) Action potential arrives in synaptic terminal, and stimulates opening of voltage-regulated calcium channels. The resulting calcium influx triggers exocytosis of synaptic vesicle contents. The phospholipids of the vesicle membranes are recycled, either from fusion of vesicles then later formation of new vesicles from the same molecules; or from the kiss-and-run model, in which the vesicle phospholipids are not incorporated into the membrane at all, but remain as vesicles that can be refilled with neurotransmitter.
206) Synaptic plasticity is the changeability of synapses, necessary for development and continued learning in the nervous system. Neuroglia play an important role in healing of damaged neural tissue. Schwann cells in the PNS facilitate regrowth of severed axons. CNS glia seal off and scar a damaged region. Neurotrophic factors are important in maintaining active synapses.
207) Loss of myelin slows or stops impulse conduction, preventing descending tracts from regulating spinal motor neurons, and leading to loss of coordination and the ability to correct for gravity, movement, and so on.
208) Symptoms listed all involve loss of motor control. The CNS axons involved in initiating and controlling movement are myelinated, thus loss of myelination slows or eliminates conduction of action potentials in these cells. Early on, many si arrive normally at spinal motor neurons to produce movement, but enough signals are missing to cause noticeable alter in motor control.
In other words, loss of myelin slows or stops impulse conduction and leads to loss of coordination and the ability to correct for gravity, movement, and so on. Gated ion channels should be intact at the nodes of Ranvier, but missing elsewhere along the axon. Nodes are generally far enough apart that without myelin, sufficient positive current from one active node does not arrive at the next node to bring it to threshold as quickly as normal or at all, and impulse conduction slows or stops.
209) Maximum frequency is mostly dependent upon the duration of the absolute refractory period, which determines the upper limit. The diameter of the axon, amount of myelination present, and the magnitude of the Na+ and K+ gradients across the axonal membrane all affect action potential velocity may also play a secondary role.
210) (Note to instructor: Students must have already completed the endocrine chapter(s) in order to answer this.)
Neurotransmitters usually do not enter the cell, thus must combine with receptors on the membrane, using mechanism to the amino acid-derivative hormones. Similarities include opening channels in the postsynaptic cell membrane, leading to depolarization of the neuron. In endocrine target cells, the arrival of the stimulus begins a different sequence of events, such as triggering an enzyme cascade, and second messenger systems.
211) Your lab partner can increase the stimulus frequency instead. A higher frequency of stimuli can result in temporal summation of graded potentials such that the lower voltages sum to threshold.
212) Assuming the specificity of the voltage-regulated sodium and potassium channels is absolute, the axons will be unable to generate action potentials. The sodium channels will open and close, but there will be no ionic current through them. The students will still see hyperpolarization, as the potassium efflux should be unaffected by lithium.
213) Schwann cells, present in the PNS but not the CNS, facilitate regrowth of severed axons. This means that people do not recover as well from CNS injury compared to PNS injury. It is possible that there is something fundamentally different in CNS axons compared to PNS axons that accounts for this effect. To test for this, Schwann cells could be transplanted into the spinal cord or brain and CNS axons observed for regrowth. Such experiments have been done, and it is the case that CNS axons are capable of regrowth in the presence of Schwann cells. Identification of chemical or physical factors in the Schwann cells would advance this field of research.
214) (Note to instructor: It is best to have demonstrated this in class or on a handout at some time prior to the exam.)
Diagrams and graphs should resemble those in Figure 8.7 in the chapter, except that the number of synaptic inputs sho be greater (see Fig. 8.24), and a set of graphs should be drawn for each input. Diagrams of a multipolar neuron with the different synapses indicated should be produced. There should be a total of three to five synapses, depending on wheth or not the student assumes the three synapses described for situation 1 are different from those for situation 2. The graph of summation should resemble Figure 8.24c,d. In situation 1, the student should choose amplitudes that sum to a value below +15 mV (the PSP that was 15 mV at the synapse is smaller when it reaches the trigger zone). In situation 2, the student should choose amplitudes that sum to a value equal to or above +15 mV.
215) K+ cannot move because, without potassium channels, the membrane is not permeable to it. Na+ will move into the cell because both its chemical and electrical gradients favor movement in. Cl- leaves the cell due to the electrical gradient (the negative resting potential repels it).
216) EK+ = 61 log 150/5 = 90.10 mV, ENa+ = 61 log 175/15 = 65.08 mV, ECl- = -61 log 40/40 = 0 m
217) X AP/2 msec × 1000 msec/1 sec = 500 APs per second.
218) Graph should be similar to Figure 8.9 in the chapter.
219) Graph should resemble Figure 8.9 in the chapter.
220) It would be appropriate for the student to draw action potentials on the graph beginning at the point where the resting potential drifts up to threshold, and decreasing in frequency as the resting potential approaches. Very gradually, a cell's resting membrane potential would increase until it reached and stabilized there. At that point the ions would be in equilibrium, and no further net flow of charge would occur. There would be no effect on ability to generate action potentials INITIALLY, but with the disappearance of the differential distribution of sodium and potassium upon which the action potential depends, action potentials would gradually come to a stop. This points out the fact that during any SINGLE action potential, so few ions cross the membrane that there is no significant change in ion concentrations. Thousands of action potentials would be required before the absence of the sodium-potassium pumps would be noticeable.
221)
222) Graphs should resemble Figure 8.17 in the chapter.
223) See Figure 8.17 in the chapter.
224) 1. no action potential; membrane potential would show a stimulus pulse that reaches threshold, however
2. prolonged action potential, as repolarization is slowed in absence of potassium efflux; peak may be higher as well
3. normal action potential
4. prolonged action potential, as sodium influx lasts longer; peak may be higher as well
225) In both cases, action potential is prevented, because the postsynaptic potential is blocked. Membrane potential would remain at resting potential, because even a subthreshold postsynaptic potential fails to appear in the absence of neurotransmitter action.
226) Both AMPA and NMDA receptors are located on the postsynaptic cells (dendrites) and require binding of the excitatory neurotransmitter glutamate for activation. When glutamate binds to the AMPA receptor, the channel opens and Na enters the cell. This causes depolarization of the immediate postsynaptic cell or dendrite. This depolarization causes Mg2+ ions to be "kicked out" of the NMDA receptor channel; hence, Mg2+ is no longer acting as a channel blocker. If at the same time glutamate is bound to the NMDA receptor then the channel gate is open and Ca2+ enters the cell. The entry of Ca2+ triggers 2nd messenger pathways that result in an increase in the number of glutamate receptors inserted into the post-synaptic membrane. This increases the probability of an increase in the postsynaptic response or depolarization to glutamate that is referred to as long-term potentiation.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) The first multicellular animals to develop neurons were
A) mollusks and sea stars.
B) jellyfish and sea anemones.
C) fish and sea monkeys.
D) flatworms and sea urchins.
E) segmented worms and sea horses.
2) The first multicellular animals to develop neurons had structures known as nerve A) webs. B) mazes. C) nets. D) tracts. E) cords.
3) Simple reflexes in a worm are integrated within a segment rather than in the brain, because worms
A) do not have brains.
B) have a neural network within each segment.
C) have a ganglion at each segment.
D) do not have a nervous system.
4) The brain region can be identified by its folds and grooves is the
A) cerebellum only.
B) cerebrum only.
C) medulla oblongata only.
D) cerebrum and medulla oblongata.
E) cerebellum and cerebrum.
5) Which of these have the most advanced nervous system?
A) sea anemones B) jellyfish
C) segmented worms D) flatworms
6) The earliest embryonic region from which the entire nervous system eventually develops is the A) ependyma.
B) neural tube.
C) neural crest.
D) neural plate.
E) ventricle.
7) The peripheral nervous system develops from the A) neural tube. B) neural crest. C) neural plate.
8) The pons develops from the A) hindbrain. B) forebrain. C) midbrain. 8)
9) Which of these does NOT contribute significantly to the protection of the brain?
A) subarachnoid space
B) cerebrospinal fluid (CSF)
C) cerebral space
D) cranium
E) dura mater
10) Cerebrospinal fluid is secreted by the
A) arachnoid villi.
B) choroid plexus.
C) ventricles.
D) pia mater.
E) frontal sinuses.
11) The brain has a (high or low?) demand for oxygen, and receives about % of the total blood volume in circulation.
A) low, 15 B) high, 35 C) low, 35 D) high, 15 E) high, 50
12) The brain consumes about half of the circulating in the body.
A) potassium B) sodium C) glucose D) oxygen E) fatty acids
13) Cell bodies of sensory neurons are located in
A) ventral root ganglia.
B) ventral horns.
C) dorsal root ganglia.
D) propriospinal tracts.
E) dorsal horns.
14) The mixed cranial nerve that projects to and from internal organs, muscles, and glands is the nerve.
A) trochlear
B) spinal accessory
C) vagus
D) trigeminal
E) glossopharyngeal
15) Which is NOT located in the medulla oblongata?
A) the pyramids, where tracts cross to the opposite side of the body
B) centers for vomiting control
C) centers for eye movement control
D) centers for breathing control
E) centers for blood pressure control
16) Which of these functions is NOT related to the reticular formation?
A) sleep
B) pain modulation
C) arousal
D) menstrual cycle
E) muscle tone
17) Which statement about the hypothalamus is FALSE?
A) The hypothalamus contains various centers for behavioral drives such as hunger and thirst.
B) It receives input from multiple sources.
C) It receives sensory fibers from the optic tract, ears, and spinal cord.
D) Hypothalamic trophic factors control the release of anterior pituitary hormones.
18) The structure that connects the two cerebral hemispheres is the
A) H-shaped grey matter.
B) basal nuclei.
C) corpus callosum.
D) hippocampus.
E) suprachiasmatic nucleus.
19) The brain area(s) that has/have a cortex is/are the
A) medulla oblongata only.
B) cerebellum only.
C) cerebrum only.
D) cerebrum and medulla oblongata.
E) cerebrum and cerebellum.
20) Which is a system that influences motor output, according to Larry Swanson?
A) emergent
B) behavioral state
C) diffuse modulatory
D) emotional state
E) developmental state
21) The most primitive region of the cerebrum is probably the
A) corpus callosum.
B) basal nuclei.
C) pons.
D) limbic system.
E) reticular system.
22) Which functions in the control of movement?
A) basal nuclei only
B) amygdala only
C) hippocampus and amygdala
D) hippocampus only
E) All of the above function in the control of movement.
23) Reasoning arises in the outer layer of neurons of which of the following?
A) hippocampus
B) cerebrum or cerebral cortex
C) basal nuclei
D) amygdala and hippocampus
E) amygdala
24) The brain's integration of sensory stimuli is called
A) perception.
B) cognition.
C) emotion.
D) lateralization.
E) proprioception.
25) Language and verbal skills tend to be side of the brain.
A) randomly located with respect to the left or right
B) concentrated on the left
C) equally distributed between the left and right
D) concentrated on the right
26) The internal clock of mammals appears to be located in the
A) brain stem.
B) choroid plexus.
C) pons.
D) suprachiasmatic nucleus.
E) pituitary gland.
27) Substances that have been isolated from the blood and have been shown to induce sleep have also been linked to the system.
A) integumentary
B) urinary
C) respiratory
D) reproductive
E) immune
28) Which brain area is considered to be a key integrating center for homeostasis?
A) brain stem
B) hypothalamus
C) medulla
D) pituitary gland
E) thalamus
29) Symptoms of the fight-or-flight reaction include all of these EXCEPT
A) increased blood pressure.
B) pupillary dilation.
C) pounding heart.
D) hunger.
E) sweating.
30) The hormone that is released to increase the fight-or-flight reaction is
A) antidiuretic hormone.
B) epinephrine.
C) prolactin.
D) oxytocin.
E) thyroid hormone.
31) The brain area described as the center for emotions is the A) cerebellum.
B) amygdala.
C) hypothalamus.
D) pons.
E) suprachiasmatic nucleus.
32) An important structure in both learning and memory is the A) cerebellum.
B) hippocampus.
C) hypothalamus.
D) medulla.
E) pons.
33) The inability to remember newly acquired information is called
A) anterograde amnesia.
B) implicit amnesia.
C) short-term amnesia.
D) retrograde amnesia.
E) discombobulation.
34) Which of these has a higher concentration in cerebrospinal fluid than in the blood?
A) Ca2+ B) K+ C) H+ D) Na+ E) HCO3-
35) Declarative memories are stored in cortical areas of the lobes.
A) amygdala B) temporal C) frontal D) parietal E) cerebellar 35)
36) Reflexive memories are stored in areas of the
A) cerebellum.
B) occipital lobe.
C) temporal lobe.
D) frontal lobe.
E) parietal lobe. 36)
37) Altered effectiveness of synaptic transmission occurs in A) training.
B) long-term potentiation.
C) consolidation.
D) synaptic plasticity.
E) synchronicity. 37)
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match these terms with their descriptions.
38) carry mostly efferent signals from the brain
39) white matter that remains in the spinal cord
40) unmyelinated, consists of cell bodies, dendrites, and axon terminals
41) carry sensory information to the brain
42) myelinated axons with very few cell bodies
Match these terms with their descriptions.
43) swellings containing sensory cell bodies
44) tracts of axons that transfer information up and down the spinal cord
45) carries motor information from spinal cord to muscles and glands
46) clusters of gray matter in the brain
47) sensory fibers enter this part of the "H" shape
Match these brain areas with their descriptions.
48) composed of many small nuclei, an area that integrates and relays sensory information that passes through it
columns
dorsal horns
49) receives sensory input from the inner ear's receptors for equilibrium and balance
50) composed of distinct regions of gray and white matter, a section of the brain that develops with sulci and gyri
51) playing key roles in homeostasis, an area that contains centers for hunger and thirst, as well as controlling the autonomic nervous systems
Match these brain areas with their locations.
52) all lobes of the cerebrum
53) parietal lobe
54) temporal lobe
55) occipital lobe
A) auditory cortex
B) association areas
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
56) In annelids, simple reflexes occurring within a segment (i.e., without brain input) are possible because of ; in vertebrates these reflexes are called . 56)
57) Under normal circumstances, the only fuel source for the neurons of the brain is . 57)
58) The three sections of the brain stem are , , and . 58)
59) The measurement of brain activity is recorded by a procedure known as the 59)
60) In vertebrates, the CNS is protected by bony cases, the brain inside the , while the spinal cord runs through a canal inside the 60)
61) The is a salty fluid continuously secreted into hollow cavities known as This fluid is secreted into these cavities by the , a specialized tissue consisting of capillaries and transport epithelium. 61)
62) Extracellular fluid is a protective part of the CNS. The fluid, found inside the pia mater, and the fluid, found in ventricles between the pia mater and arachnoid membrane, make up the extracellular environment for neurons. They communicate across leaky junctions of the membrane and the cell layer that lines the ventricles.
62)
63) The only fuel source for neurons under normal circumstances is . Low blood levels of this fuel source is termed , which can lead to confusion, unconsciousness, and eventually death. In order to synthesize enough ATP to continually transport ions, the neurons also exhibit high demand. To supply these needs about % of the blood pumped by the heart goes to the brain.
64) Two areas of the brain missing the blood-brain barrier are the and 64)
65) is a naturally occurring stimulant in food, which acts upon receptors. 65)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
66) There are three divisions of the brain. Make a table and place each of the six regions of the brain in one of the three divisions.
67) Do the terms vertebral column and spinal cord mean the same thing? Explain.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
68) Some types of antihistamines make one sleepy, others do not. This difference is partly because of a difference in
A) ATP-dependence of drug transport.
B) lipid solubility.
C) whether or not the drug mimics the hormone melatonin.
D) the type of receptor involved.
69) A complete spinal cord transection injury results in paralysis, which is the inability to do which of the following?
A) move voluntarily and feel
B) move voluntarily
C) feel
D) move at all and feel
E) move at all
70) General anesthetics keep surgical patients unconscious by reducing activity in the
A) hippocampus.
B) medullary pyramids.
C) reticular formation.
D) lateral ventricles.
E) corpus callosum.
71) Caffeine and related stimulants exert their effects by A) inhibiting a specific neuromodulator. B) mimicking a specific neurotransmitter.
C) inhibiting a specific neurotransmitter. D) mimicking a specific neuromodulator.
72) Experimental animals become tamer and more sexually active following damage to the A) hippocampus. B) amygdala.
C) hypothalamus. D) suprachiamatic nucleus. E) corpus callosum.
73) You used to love to drink milk when you were a child. Lately, you notice that your stomach hurts and you experience bloating and discomfort when you drink it. It no longer want to drink milk when you see someone else drinking it. What kind of learning has occurred? A) associative B) sensitization C) anterograde D) habituation
74) When a puppy is scolded "No!" each time he chews on your homework, eventually he learns to leave your homework alone. This type of learning is called A) sensitization. B) habituation. C) nonassociative. D) associative.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match these functions with the correct brain area.
75) contains corticospinal tracts, the pyramids, and control centers for breathing, swallowing, and blood pressure
76) network to coordinate arousal and sleep, but also involved in blood pressure regulation and pain modulation
77) small area that relays signals for auditory and visual reflexes as well as eye movement
78) relay station for transfer of information between the cerebrum and cerebellum; coordinates breathing control with other areas
For the structures listed below, choose one of the following.
79) cerebral cortex
80) limbic system
81) corticospinal tracts
A) midbrain
B) reticular formation
C) pons
D) medulla oblongata
A) structure is composed of gray matter
B) structure is composed of white matter
82) ventral horn
83) basal ganglia
84) corpus callosum
A) structure is composed of gray matter
B) structure is composed of white matter
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
85) Describe the physical protection provided by the cerebrospinal fluid.
86) Describe cerebrospinal fluid flow from secretion to absorption.
87) Discuss the functions of the blood-brain barrier. What cellular characteristics contribute to its effectiveness?
88) Describe a lumbar puncture and explain its purpose.
89) Explain neural plasticity in the brain, in the context of recovery from injury.
90) Give a brief summary of CNS control of movement.
91) Trace the language pathway of signals from the eye (written words) or the ear (spoken words) to the motor cortex. Discuss the two regions of the cortex involved in this pathway. Describe their location and the communication problems that can occur if there is damage to either area.
92) Describe the embryonic development of the nervous system.
93) Describe the phases of a normal sleep cycle.
94) How are moods similar to or different from emotions?
95) Define implicit and explicit memory.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
96) There is a story about an autopsy having been performed on a space alien in New Mexico, many decades ago. Assuming that this alien was as well-educated and trained on its planet similar to how NASA educates and trains astronauts on Earth, what feature would be expected in the alien's brain?
A) a system of fluid-filled cavities deep in the brain
B) glandular structures resembling the pineal and pituitary
C) a thick band of fibers connecting right and left hemispheres
D) at least 12 pairs of cranial nerves
E) an enlarged area with surface grooves and folds 96)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
97) If a diabetes mellitus patient always has high blood glucose, what is likely to happen to the nervous system, and what are the possible outcomes?
98) If sensitization is the opposite of habituation, and sensitization is adaptive, would habituation be considered maladaptive? Why or why not?
99) The blood-brain barrier protects the brain from harmful substances in the blood, but it also protects the brain from potentially therapeutic chemicals that may reduce the size of brain tumors by killing cancer cells, alleviate depression, and aid in patient recovery from stroke or spinal cord injury. Two methods are currently being researched to get these helpful chemicals past the blood-brain barrier. The two methods are termed "molecular Trojan Horse" and osmotic "blood-brain barrier disruption." Based on their names, hypothesize how these methods might allow chemicals to pass through the blood-brain barrier.
100) Ariana is a student who listens attentively in class and recopies and elaborates on her notes from several textbooks the minute she gets home from school. She studies with a group that explains concepts to each other, and they write on a big blackboard while they work. She makes flashcards out of the few vocabulary terms she has a hard time keeping straight, and goes through those between classes and in spare moments. What kind(s) of memory are being developed by Ariana, and by which methods?
101) You are walking to class, thinking about the complexities of physiology, when you trip over an uneven place in t sidewalk, and fall. Unhurt but embarrassed and angry, you jump up and look around to see if anyone is watchin your knowledge of neuroanatomy and function, explain how the following areas of the brain might be involved situation:
A. cerebrum
B. cerebellum
C. limbic system
102) In 1848, a railroad foreman named Phineas Gage was injured in an explosion, when a tamping iron penetrated his skull and caused brain damage; surprisingly, he survived. The rod was 1.25" in diameter and 3.5' long. After the accident he was able to speak, get himself up and down from a cart, and climb a flight of stairs to see the local physicians. Years later, the doctors reported that he physically recovered, but the balance between his intellectual facilities and animal propensities was destroyed. He was no longer mild-mannered, kind, and respectful; he grew obstinate, ill-tempered, and showed little self-restraint. Based on this story, which area(s) of the brain (and/or systems) do you think he injured and why?
103) Your best friend, Fred, was injured when he fell several meters from a cliff, but his vital signs are stable and all lacerations have been repaired. His physician is in the process of determining what neural damage he has sustained. What may be damaged if Fred is unable to walk normally? (Hint: Consider various types of factors that influence motor output, as well as the structures immediately responsible for movement.)
104) Ginger was a happy, healthy 17-year-old girl. One day while sitting at the kitchen table with her family, she looked up with an odd expression, complained that her head hurt, dropped her fork, and fell off her chair as she lost consciousness. Her father caught her before her head hit the floor. Ginger regained consciousness at the hospital, where it was determined that she had suffered from a ruptured brain aneurysm. An aneurysm results when a blood vessel wall becomes progressively thinner and weaker, and can ultimately rupture, depriving of blood the areas it normally supplies. Sometimes permanent brain damage results. Ginger seems to have all of her normal functions and cognitive abilities, except she cannot see. What areas did the ruptured blood vessel possibly supply with blood? If instead of blindness she could see normally but control of eye movement was abnormal, what areas may have been damaged by loss of blood?
105) Parkinson's disease affects the cerebral basal ganglia, resulting in tremors in limbs, slowness in beginning and completing movements, and other abnormalities of muscle control. The specific population of neurons involved degenerates and thus fails to produce the neurotransmitter dopamine. An obvious treatment option to try is to administer dopamine, yet this is completely ineffective at alleviating the symptoms. Propose a reason why this treatment fails, and a related alternative to address the dopamine deficit. (Hint: Think about how the brain protects itself from chemicals in the blood.)
106) What function(s) is/are associated with the basal ganglia? Huntington's disease affects the cerebral basal ganglia, causing neural degeneration, and resulting in abnormal muscle movements and decreases in cognition. What may cause the decreased cognition? Effective treatment for Huntington's has been elusive, but recently it was shown that a cause of neuron degeneration may be calcium overload. What potential type of treatment does this suggest?
Answer Key
Testname: UNTITLED28
1) B
2) C
3) C
4) E
5) C
6) D
7) B
8) A
9) C
10) B
11) D
12) C
13) C
14) C 15) C
16) D
17) C
18) C
19) E
20) B
21) D
22) A
23) B
24) A
25) B
26) D
27) E
28) B
29) D
30) B
31) B
32) B
33) A
34) C
35) B
36) A
37) B
38) D
39) B
40) C
41) A
42) E
43) C
44) A
45) D
46) E
47) B
48) A
49) A
50) C
Answer Key
Testname: UNTITLED28
51) B
52) B
53) D
54) A
55) C
56) ganglia, spinal reflexes
57) glucose
58) medulla oblongata or medulla, pons, midbrain
59) electroencephalography (EEG)
60) skull (cranium), vertebrae (spine)
61) cerebrospinal fluid (CSF), ventricles, choroid plexus
62) interstitial, cerebrospinal, pial, ependymal
63) glucose, hypoglycemia, oxygen, 15
64) hypothalamic-hypophyseal portal system, the (vomiting center of the) medulla (medulla oblongata)
65) Caffeine (or other xanthines: theophylline, theobromine), adenosine
66)
Forebrain Midbrain Hindbrain
Cerebrum Midbrain
Cerebellum
Diencephalon Pons
Medulla Oblongata
67) The vertebral column is bone. The spinal cord is neural tissue, protected by the spine or vertebral column.
68) B
69) A
70) C
71) A
72) B
73) B
74) D
75) D
76) B
77) A
78) C
79) A
80) A
81) B
82) A
83) A
84) B
85) Because the brain floats on CSF there is less weight and, therefore, less pressure on the blood vessels and nerves attached to the CNS. The fluid also pads the brain so it is less likely to hit the cranium and risk bruising when there is a blow to the head.
86) Cerebrospinal fluid is secreted from the choroid plexus. It flows into the subarachnoid space (between the pia mater and arachnoid membrane) to surround the brain and spinal cord. CSF is absorbed back into the blood at arachnoid villi (located in the cranium).
87) This is discussed in the "9.3 Anatomy of the Central Nervous System" section of the chapter.
88) A lumbar puncture, also called a spinal tap, samples the cerebrospinal fluid from the subarachnoid space at the lower end of the spinal cord. This procedure is performed to sample the chemical environment of the brain and test for infection. An infection is indicated by proteins or blood cells found in the sample.
89) Areas of the brain involved in a body part that is removed, such as following a limb amputation, are taken over by ingrowth of synaptic connections from nearby areas, rather than the areas disappearing along with the limb. Skills present on one side of the cerebral cortex can be developed on the other side, as might happen if a right-handed person must become left-handed, or large areas of the brain are removed as treatment for epilepsy.
90) Motor output consists of somatic control of skeletal muscle. Simple somatic reflexes are controlled by centers in the brain and spinal cord. Voluntary control of skeletal muscle involves primary motor cortex and motor association areas, sensory areas, basal nuclei, and cerebellum.
91) eye → visual cortex → Wernicke's area → Broca's area → motor cortex ear → auditory cortex → Wernicke's area → Broca's area → motor cortex
Wernicke's area is located in the temporal lobe. If damage occurs here, the person cannot understand sensory input (spo visual). The resulting condition is receptive aphasia, nonsensical speech that the speaker is unaware of. Broca's area is located in the frontal lobe. If damage occurs here, the person is unable to respond using normal syntax. T resulting condition, expressive aphasia, is difficult to deal with because people who have it understand sensory input and can respond, but their statements contain the right words in random order and they are unable to correct it.
92) The earliest neural structure is the neural plate, a flat sheet of tissue located on the dorsal surface of the embryo, clearly visible at day 20 post-fertilization. The edges of the plate fold and cells of the neural crest migrate toward the midline, until a hollow neural tube is formed from the plate by about day 23. The lumen will become the fluid-filled central cavities of the CNS. The lumen is lined with ependymal cells and neural stem cells. Cells of the neural crest will continue to migrate, forming the structures of the PNS. The rest of the tube will become the CNS. By 4 weeks, three discrete swellings will form in the anterior end of the tube: forebrain, midbrain, and hindbrain. The remainder of the tube becomes the spinal cord. By 6 weeks, the cerebrum, diencephalon, midbrain, cerebellum, pons, and medulla oblongata are distinct. By 11 weeks the cerebrum is noticeably enlarged.
93) Sleep is composed of four different stages and during sleep one repeatedly cycles from one stage to another.
Stage 4 is slow-wave in deep sleep that can be identified by low-frequency high-amplitude EEG delta waves. This stag occurs more during the beginning of sleep.
Stage 3 is characterized by a lower amplitude but higher frequency EEG wave pattern.
Stage 2 is characterized by an even lower amplitude and even higher frequency EEG wave pattern. This cycle lasts for l durations as a typical 8 hour sleep progresses.
Stage 1 is REM: Rapid eye movement is characterized by dreaming and low amplitude high frequency EEG waves. Mos neurons (e.g., except eye and breathing motor neurons) are inhibited while dreaming is occurring. REM occurs for longer time periods during later parts of the sleep cycle. The EEG pattern is most similar to the alpha pa found when one is awake.
94) Moods last longer, and are relatively stable subjective feelings related to sense of well-being. Mood disorders such as depression are thought to be related to abnormal neurotransmitter action.
95) Both are a type of long-term memory. Implicit or reflexive memory is automatic and does not require conscious effort. Examples are tasks that primarily involve motor skills such as writing or throwing a ball and the memory tasks typically stored at in large part in the cerebellum and the amygdala. Explicit or declarative memory requires conscious attention, using higher-level thinking skills. These memories can be communicated.
96) E
97) With too much glucose present, the blood-brain barrier cells may remove glucose transporters from the patient's membranes. If blood glucose drops due to insulin therapy, the brain neurons may be unable to obtain sufficient glucose to function or remain alive. This can lead to a comatose state or even death.
98) Habituation is not maladaptive. During habituation, an animal shows a decrease in response to a given stimulus. This stimulus has been processed and determined to be nonthreatening or insignificant. Because the animal has been habituated to ignore this stimulus, it can fade into the background so the animal can focus on other more important stimuli. Habituation is adaptive especially in conjunction with sensitization because the animal can differentiate and ignore certain irrelevant stimuli (through habituation) and focus more intently on potentially dangerous stimuli (sensitization).
99) (Note to instructor: You may have to explain enough of the legend of the Trojan Horse for this to be a fair question.) The molecular Trojan Horse method delivers specific substances to the brain by attaching them to a protein that is norm to cross the barrier. The therapeutic chemicals are ferried across by piggybacking a substance that can cross the barrier. across the barrier, these substances can reach almost every neuron through the blood vessels that nourish the brain. The blood-brain barrier disruption method is a technique that uses a concentrated mannitol (sugar) solution. Because this solution is more concentrated than the endothelial cells of the capillaries that make up the blood-brain barrier, these cells will experience shrinkage (Chapter 5, hypertonicity). When these cells decrease in volume the tight junctions that exist between them are temporarily opened and chemicals in that area can pass through the blood-brain barrier. In actual patients who experimentally undergo this therapy, an infusion of this solution, via a catheter, temporarily opens the tight junction by osmotically disrupting the endothelial cells that make up the blood-brain barrier.
Immediately after the mannitol solution, the patients receive the chemotherapy treatment intra-arterially through the same catheter.
100) Recopying notes and asking questions about what she has learned helps consolidate the information into long-term memory. Flashcards help to develop associative learning skills, but probably in short-term memory; putting those words to use contributes to long-term storage. Explicit or declarative memory is created with the study group.
101) A. The cerebrum is involved in conscious perception and voluntary motor control. Various sensory areas of the cortex will detect the mis-step, falling, and landing on the ground. Motor areas will initiate standing up and brushing yoursel
B. The cerebellum receives a copy of the motor output from the cerebrum that controls spinal motor neurons, and also s input. The cerebellum compares the sensory and motor information to coordinate the execution of movement. Obviousl cerebellum was unable to prevent you from falling; however, your return to an upright position may be executed smoo thanks to this brain area.
C. The limbic system is involved in emotion. This is where your fear, anger, or embarrassment at falling will arise.
102) The regions damaged by the iron rod were the frontal lobes of the cerebrum. Based on what we have learned, we can hypothesize that the limbic system was most likely injured since it acts as the link between higher cognitive functions and primitive emotional responses. The limbic system contains the cingulate gyrus, which plays a role in emotions, and the amygdala, which is involved in emotion and memory. Since we can tell from the story that he definitely exhibited different emotions, we can hypothesize that these areas were injured. Based on the fact that he physically recovered, we can assume that the somatosensory cortex, mid- and hindbrain areas were unaffected.
103) Walking normally will depend upon sensory as well as motor control structures. Damage to leg nerves and muscles could impair walking, as could damage to spinal cord areas that control the muscles, and spinal cord areas that mediate relevant sensation from legs and feet. Damage to the spinal tract to and from the brain could interfere with brain influences on walking. Motor control areas in the brain that could be damaged include the cerebellum, pons, basal ganglia, and cerebral cortex. Also, damage to any area containing tracts to and from motor control areas could prevent normal signals from influencing motor output.
104) For blindness, damaged areas may include the optic nerves or the occipital lobe of the cerebrum. For loss of normal eye movement, damage to the midbrain or the oculomotor or trochlear nerves may be responsible.
105) Dopamine administered to a Parkinson's patient fails to cross the blood-brain barrier. Treatment with the dopamine precursor L-dopa, however, is effective, as this molecule can cross the barrier.
106) The basal ganglia are involved in motor control. It is possible that basal ganglia play a role in cognition as well as in motor control, or that the cerebral cortex is also affected by Huntington's. Calcium channel blockers may be developed as treatments for this disease.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Which is an adequate stimulus for a mechanoreceptor?
A) ligand
B) photon of light
C) cell swelling
D) cold temperature
E) odorant molecule
2) Which is an adequate stimulus for a chemoreceptor?
A) cell swelling
B) odorant molecule
C) cold temperature
D) vibration
E) photon of light
3) Which statement about sensory receptor cells is FALSE?
A) Many sensory receptor cells are NOT nerve cells.
B) Each type of sensory receptor responds only to the stimulus that defines the receptor.
C) Threshold is the minimal stimulus intensity required to generate an action potential.
D) A graded potential is called a receptor potential.
E) Sensory transduction converts stimuli into graded potentials.
4) A graded potential within a sensory receptor cell is a(n)
A) action potential.
C) receptor potential.
B) hyperpolarization.
D) depolarization.
5) Opening a Na+ channel in a non-neural sensory receptor cell would cause that cell to
A) hyperpolarize. B) generate an action potential.
C) depolarize.
D) decrease neurotransmitter release.
6) With the exception of olfaction, all sensory pathways first travel to the , which acts as a relay and processing station.
A) cerebrum
B) thalamus
C) hypothalamus
D) cerebellum
E) medulla oblongata
7) A receptor potential is
A) the resting membrane potential of a receptor cell.
B) the resting membrane potential of a sensory neuron.
C) always converted to an action potential in sensory receptor cells.
D) a graded potential.
E) an action potential.
8) The two-point discrimination test is used to measure
A) hearing disorders.
B) activity of taste buds.
C) receptive field size for touch receptors.
D) clarity of vision.
E) olfactory receptors.
9) Convergence describes
A) the reason why receptive fields are so small.
B) how one presynaptic sensory neurons synapses with one postsynaptic neuron.
C) how receptive fields can overlap with one another.
D) how multiple presynaptic sensory neurons synapse on one postsynaptic neuron.
E) how one presynaptic sensory neuron synapses with multiple postsynaptic neurons.
10) The larger the receptive field, the
A) fewer primary sensory neurons are involved.
B) more primary sensory neurons synapse on one secondary sensory neuron.
C) stronger the stimulus intensity required to activate a sensory receptor.
D) larger the area of the somatosensory cortex in the brain that perceives the sensation.
11) The perceptual threshold describes the
A) concept that neurons higher in the sensory pathway can dampen the intensity of a stimulus.
B) convergence of information from multiple primary sensory neuron onto a single secondary neuron.
C) intensity of stimulus required to generate an action potential.
D) intensity of stimulus required to generate a receptor potential.
12) A decrease in perception of a stimulus whose intensity has not changed due to higher neural inhibition is
A) adaptation. B) habituation. C) convergence. D) divergence.
13) The intensity of a stimulus can be determined within the central nervous system by
A) population coding and/or frequency coding.
B) population coding only.
C) frequency coding only.
D) labeled line coding only.
E) labeled line coding and/or frequency coding.
14) The modality of a stimulus can be determined within the central nervous system by
A) adequate stimulus from the sensory receptor cell.
B) frequency coding.
C) population coding.
D) lateral inhibition.
15) Tonic receptors
A) are quick to adapt to a constant stimulus.
B) detect changes in a parameter, not the extent of that change.
C) will always decrease to the point where no action potentials are generated.
D) slowly decrease the frequency of action potentials generated to a constant stimulus.
16) Phasic receptors
A) detect parameters that the body must continuously assess.
B) slowly decrease the frequency of action potentials generated to a constant stimulus.
C) are quick to adapt to a constant stimulus.
D) once threshold is reached by a stimulus will always generate action potentials.
17) Which is/are responsible for a receptor adapting to a stimulus?
A) K+ channel opening only
B) Na+ channel inactivation or K+ channel opening
C) Na+ channel opening only
D) K+ channel inactivation only
E) Na+ channel inactivation only
18) Which is NOT a somatosensory modality?
A) vision
B) proprioception
C) touch
D) temperature
E) nociception
19) Which statement about pathways for somatic perception projection is correct?
A) The longest of the secondary sensory neurons transmit fine touch and proprioceptive information.
B) The synapse for the secondary to tertiary sensory neuron is within the medulla.
C) Primary sensory neurons that respond to cold sensation project to the same region of the somatosensory cortex.
D) Primary sensory neurons from the hands project to a specific region of the somatosensory cortex.
E) The tertiary sensory neurons cross-over the body's midline.
20) The vibration receptor whose nerve endings are surrounded by layers of connective tissue layers is the
A) Merkel receptors.
B) Ruffini corpuscle.
C) root hair plexus.
D) Meissner's corpuscle.
E) Pacinian corpuscle.
21) Sensory receptors that respond when body temperature is below normal are called
A) cold receptors.
B) photoreceptors.
C) warm receptors.
D) All receptors respond to temperatures above and below body temperature (no unique name). 21)
22) Nociceptors are responsible for the perception of
A) pain only.
B) skin stretch only.
C) pain and skin stretch.
D) pain and itch.
E) itch only.
23) Sharp, localized (fast) pain is rapidly transmitted to the central nervous system along
A) small, unmyelinated C fibers.
C) small, myelinated A-delta fibers.
B) large, unmyelinated C fibers.
D) large, myelinated A-beta fibers.
24) Visceral pain is poorly localized and can be perceived to come from a region of the body that is different from its actual location; this is called
A) tonic reception.
B) adaptation.
C) analgesia.
D) latency.
E) referred pain.
25) Chronic pain is
A) pathological and treated by analgesic drugs.
B) only treated by analgesic drugs.
C) only pathological.
D) only the result of short-term changes in the nervous system.
26) Chemicals such as histamine, prostaglandins, serotonin, and substance P
A) only inhibit nociceptors.
B) only activate nociceptors.
C) only sensitize and activate nociceptors.
D) sensitize, activate and inhibit nociceptors.
E) only sensitize nociceptors.
27) In addition to temperature, cold receptors respond to A) capsaicin. B) menthol. C) alcohol. D) water.
28) The gate control theory of pain modulation states that pain transmission can be blocked by
A) tonic activity of the inhibitory neurons in the dorsal horn.
B) cold stimulation of the A-delta fibers.
C) mechanical stimulation of A-beta fibers.
D) stimulation of C-fibers.
29) β-endorphin is produced from the same prohormone as
A) adrenocorticotropin (ACTH).
B) insulin.
C) thyroxine.
D) aldosterone.
E) glucagon.
30) Neuronal cells that are short-lived and are frequently replaced are
A) olfactory sensory neurons.
B) gustatory receptors.
C) Pacinian corpuscles.
D) retinal cells.
E) nociceptors.
31) When Golf is activated, which steps in the olfactory cells lead to their depolarization?
A) increases in the closure of cAMP gated cation channels only
B) increases in cAMP concentrations only
C) increases in adenylyl cyclase activity, cAMP concentrations and closure of cAMP gated cation channels
D) increases in adenylyl cyclase only
E) increases in adenylyl cyclase activity and cAMP concentrations
32) Gustatory cells that respond to sour through release of serotonin are called
A) basal taste cells.
C) type I taste cells.
B) type II taste cells.
D) type III taste cells.
33) Gustatory cells that respond to sweet, bitter and umami are called
A) type II cells. B) type III cells. C) type IV cells. D) type I cells. 33)
34) is released from type II cells to stimulate primary gustatory neurons.
A) Glutamine
B) ATP
C) Serotonin
D) Gustducin
E) Acetylcholine
35) Umami is
A) another name for salty taste.
B) the name of the ion channel activated by glutamate.
C) activated by glutamate and nucleotides.
D) a flavor enhancer that is part of olfaction.
36) Signal transduction in the type II taste cells relies on the G protein A) Golf B) transducin. C) gustducin. D) Ggus 36)
37) There are taste (gustation) sensations. A) 20
38) The loudness or intensity of a sound wave is related to its A) amplitude. B) duration. C) pitch. D) frequency.
39) The pitch of a sound wave is related to its A) duration. B) frequency. C) amplitude. D) decibels.
40) The primary purpose of the middle ear bony structures (maleus, incus and stapes) is to
A) transmit otitis media to the cochlea.
B) amplify the vibration as it conducts to the cochlea.
C) transduce the sound waves into vibration.
D) dampen the vibration as it conducts to the cochlea.
E) equalize pressure in the middle ear.
38)
39)
40)
41) The ion channels that transduce the vibration of the cochlea changes membrane potentials are located on the
A) stereocilia.
B) cochlear duct.
C) tectorial membrane.
D) basilar membrane.
E) helicotrema.
42) The ear canal ends at the
A) vestibule.
B) pinna.
C) cochlear oval window.
D) malleus.
E) tympanic membrane.
43) The bones within the middle ear connect the
A) cochlea to the oval window.
B) cochlea to the tympanic membrane.
C) oval window to the round window.
D) tympanic membrane to the round window.
E) tympanic membrane to the oval window. 43)
44) Sound waves are converted into vibrations by the
A) oval window.
B) round window.
C) cochlea.
D) malleus.
E) tympanic membrane.
45) A structure that connects the middle ear with the pharynx is the
A) pinna.
B) bony labyrinth.
C) eustachian tube.
D) auditory meatus.
E) membranous labyrinth. 45)
46) The receptors of equilibrium and hearing are the
A) supporting cells.
B) ampullae.
C) utricles.
D) saccules.
E) hair cells. 46)
47) The structure that partially covers the organ of Corti and is attached to the stereociliar of the hair cells is the
A) endolymph.
B) tectorial membrane.
C) basilar membrane.
D) stapedius.
E) perilymph. 47)
48) The structure that separates the cochlear duct from the tympanic duct is the
A) membranous labyrinth.
B) bony labyrinth.
C) tectorial membrane.
D) basilar membrane.
E) stapedius.
49) The highest frequency sound is detected by
A) the frequency at which the stereocilia vibrate.
B) hair cells located near the oval window end of the basilar membrane.
C) hair cells located near the helicotrema end of the basilar membrane.
D) hair cells located near the middle of the basilar membrane.
E) unique hair cells located anywhere along the basilar membrane. 49)
50) Louder noises result in action potentials in the sensory neuron that are
A) more rapid.
B) less rapid.
C) broader.
D) shorter.
E) taller. 50)
51) Collateral pathways take vestibular receptor signals from the medulla to the
A) thalamus and reticular formation.
B) cerebellum only.
C) reticular formation and cerebellum.
D) thalamus only.
E) reticular formation only.
52) The hair cell of the cochlea is depolarized when the stereocilia are bent
A) towards the tallest stereocilia.
B) in any direction.
C) towards the smallest stereocilia.
D) towards the middle stereocilia.
E) Hair cells are not depolarized by bending of the sterocilia. 52)
53) between hair cell stereocilia open and close ion channels.
A) Kinocilia B) Utricles C) Tip links D) Otoliths
54) Which structures monitor rotational acceleration of the head?
A) maculae of the utricle only
C) cristae of the semicircular canals
53)
54)
B) maculae of the saccule only
D) maculae of the utricle and saccule
55) Sensations of the forces of gravity and linear acceleration are detected in the
A) organ of Corti.
B) cochlea.
C) saccule and utricle.
D) ossicles.
E) semicircular canals.
55)
56) The cilia of the hair cells of the semicircular canals are embedded in the A) cristae. B) saccule. C) ampullae. D) cupula. E) utricle. 56)
57) The hair cells of utricle and saccule are in A) ampullae. B) cupulae. C) cristae. D) otoliths. E) maculae.
58) Our perception of the pull of gravity and linear acceleration is the result of A) changes in the pressure exerted by the cupula on hair cells.
B) vibrations of the tectorial membrane striking hair cells.
C) the movement of the otolith membrane within the ampullae of the semicircular canals.
D) force applied by the otolith membrane on hair cells of the maculae.
59) The hair cell of the semicircular canal hyperpolarize when the stereocilia are bent A) towards the kinocilium.
B) in any direction.
C) towards the longest stereocilia.
D) away from the kinocilium.
57)
58)
E) Hair cells are not hyperpolarized by bending of the sterocilia. 59)
60) The vitreous chamber of the eye
A) is located between the lens and the iris.
B) contains the lens.
C) contains blood vessels that nourish the retina.
D) helps to maintain the structure of the eyeball. 60)
61) The opening in the eye through which the light passes on to the retina is the A) fovea.
B) conjunctiva.
C) pupil.
D) lens.
E) cornea.
62) The ciliary muscle helps to control the A) production of aqueous humor.
C) shape of the lens.
61)
62)
B) movement of the eyeball.
D) amount of light reaching the retina.
63) An area of the retina that contains only cones and is the site of sharpest vision is the A) inner segment.
B) fovea.
C) optic disc.
D) outer segment.
E) tapetum lucidum.
64) Accommodation describes the focusing of light on the retina by changing
A) the shape of the lens.
C) distance of the retina from the lens.
63)
64)
B) pupillary diameter.
D) the shape of the cornea.
65) A blind spot in the retina occurs where
A) the fovea is located.
B) rod cells are clustered to form the macula.
C) amacrine cells are located.
D) the optic nerve leaves the eye.
E) ganglion cells synapse with bipolar cells.
66) Which cells are NOT found in the retina?
A) cones B) rods C) bipolar D) amacrine E) vertical
67) The photosensitive pigment derived from vitamin A is
A) cGMP.
B) retinal.
C) rhodopsin.
D) transducin.
E) opsin.
68) On a dark night, the rods have a high concentration of A) cGMP. B) opsin. C) kinase. D) cAMP. 68)
69) Which cells involved in processing visual information in the retina synapse with the rods?
A) bipolar cells only
B) ganglion cells only
C) horizontal, ganglion, and bipolar
D) horizontal and bipolar cells only
E) horizontal cells only
70) Photoreceptors secrete the neurotransmitter
A) acetylcholine.
C) dopamine.
B) norepinephrine.
D) glutamate.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the type of receptor with the appropriate description.
71) The most studied examples of this type are phasic receptors called Pacinian corpuscles.
72) These receptors slowly adapt between 20-40° C.
73) These receptors respond to stimuli that can damage body tissues and lead to the perception of pain.
74) These are probably the oldest sensory receptors as evidenced by their existence in primitive animals that do not have formalized nervous systems.
A) nociceptors
B) chemoreceptors
C) touch receptors
D) thermoreceptors 71) 72) 73) 74)
Match the stimulus to the type of receptor that typically responds to it.
75) oxygen
76) pH
77) stretch
78) pressure
Match the specific receptor to its typical stimulus.
79) texture
80) flutter
81) stretch of skin
82) vibration
chemoreceptor
mechanoreceptor
83) temperature A) free nerve ending B) Ruffini corpuscle C) Pacinian corpuscle
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
84) A sensory receptor is a that converts a stimulus into electrical graded potentials. 84)
85) A stimulus below the will activate sensory neurons, but the signal will not reach the conscious brain because higher neurons dampen it. 85)
86) The brain's association of specific group of receptors with a specific modality is called 86)
87) Sensory neurons that adapt and maintain their firing as long as the stimulus is present are called 87)
88) are sensory receptors that respond to changes in a stimulus by altering their firing which rapidly stops as the stimulus is maintained. 88)
89) Activation of a leads to the perception of pain and itch. 89)
90) Gustatory receptors are located on 90)
91) Olfactory receptor cells extend into the mucus layer. 91)
92) Activation of Golf in the olfactory receptor cells causes to open, which causes the frequency of action potentials to . 92)
93) The initial response to sweet, bitter and umami involves binding to a receptor, which activates the protein whereas salty and sour stimulate 93)
94) Primary sensory neurons transmitting information on sweet and umami are activated by release of whereas sour are activated by release of 94)
95) is the fluid within the vestibular and tympanic duct of the cochlea. 95)
96) Endolymph is a unique fluid in the cochlear duct that contains more ions and fewer ions than the typical extracellular fluid. 96)
97) are sensory structures within the ampulla of semicircular canals that contain the hair cells. 97)
98) is the fluid contained in the vestibular apparatus. 98)
99) The hair cells of the cochlear duct are located in the 99)
100) hearing loss results from conditions that affect the ability of sound wave that have entered the external ear from generating/transmitting a vibration that will reach the cochlea. 100)
101) hearing loss occurs because of damage to the structures of the inner ear. 101)
102) cells transmit signals from photoreceptors to ganglion cells. 102)
103) The bending of light as it passes through media of different densities is called . 103)
104) Human eyes are sensitive to light in the visible spectrum between the wavelengths of 104)
105) A photoreceptor cell can be stimulated by a single on light. 105)
106) ganglion cells transmit information about texture, while ganglion cells transmit information about movement. 106)
107) For a person with the vision problem called , the focal point of the object is focused in front of the retina leading to blurring of distant objects. 107)
108) is the loss of accommodation that occurs with age due to a loss of lens elasticity. 108)
109) is a condition that causes blurred vision due to the cornea and/or lens not being perfectly shaped. 109)
110) The adjusts the shape of the lens to keep objects in focus. 110)
111) As an object moves closer to the eye, the ciliary muscle making the lens in order to keep the object in focus. 111)
112) Because of involvement of the , pain may be accompanied by emotional distress and nausea or sweating. 112)
113) Nociceptors activate pathways that provide for the conscious perception of the pain. 113)
114) Nociceptors activate pathways that provide protection by allowing rapid removal of a stimulated area from a stimulus. 114)
115) receptors respond to damaging heat as well as capsaicin (chili peppers). 115)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
116) A molecule that prevents substance P from binding to its receptor would
A) stimulate a painful sensation.
B) decrease transduction from chemoreceptors.
C) increase the perception of touch.
D) change the perception of hot and cold stimuli.
E) decrease the perception of pain.
117) Inhibiting adenylyl cyclase in olfactory sensory neurons would
A) reduce the sensitivity of these receptors.
B) increase the sensitivity of these receptors.
C) expand the range of sensitivity of these receptors.
D) convert the olfactory receptors from phasic to tonic receptors.
E) have no effect on these receptors.
118) After an injury, Sameer has difficulty recognizing and interpreting certain sounds. These symptoms imply damage to the
A) middle ear. B) external ear. C) auditory cortex. D) cochlea.
119) The release of neurotransmitter from a vestibular hair cell at the synapse with a sensory neuron would increase
A) when the stereocilia are equally displaced to either side of the kinocilium.
B) when the stereocilia of the hair cell are displaced away from the kinocilium.
C) in response to any mechanical stimulation of the hair cell.
D) when the stereocilia of the hair cell are displaced toward the kinocilium. 119)
120) Low frequency sound waves create the maximum displacement of the basilar membrane , where that membrane is .
A) near the oval window, stiff
B) in the middle, stiffer
C) near the distal end, stiff
D) near the oval window, flexible
E) near the distal end, flexible
121) Movement of the cupula in the ampullae of the semicircular canals allows detection of
A) linear acceleration.
B) high frequency sound.
C) rotational acceleration.
D) low frequency sound.
E) gravity.
122) For astronauts in space (without gravity), the otoliths in the macula would respond to
A) linear acceleration and head position. B) rotational acceleration only.
C) linear acceleration only.
D) head position only. 122)
123) A viral infection involving the vestibular nuclei may result in
A) local paralysis.
B) loss of sight.
C) a sense of dizziness.
D) high blood pressure.
E) loss of hearing. 123)
124) A decrease in the release of neurotransmitter from the photoreceptor would indicate a(n)
A) increase in light intensity.
B) no light reaching the retina.
C) change in focus of the lens onto a distant object.
D) decrease in light intensity.
125) If the sodium pump in the membranes of the photoreceptors were completely blocked, the result would be
A) darkness (blindness).
B) an increase in visual acuity.
C) the cells would not be able to produce glutamate.
D) grey images as only rods would function.
E) bright white light as all cones would be activated.
126) If a person's cornea is flatter than normal, this person has
A) presbyopia.
B) myopia.
C) hypopia.
D) hyperopia.
E) astigmatism.
127) The following steps occur in rods when they are excited by a photon of light. Place them in the corre sequence.
1. Membrane CNG channels close.
2. cGMP is decreased.
3. The membrane hyperpolarizes and glutamate release decreases.
4. Transducin is activated.
5. Rhodopsin is activated.
A) 3, 5, 2, 1, 4 B) 4, 5, 2, 1, 3 C) 1, 5, 2, 4, 3 D) 1, 3, 4, 5, 2 E) 5, 4, 2, 1, 3
126)
127)
128) A sudden flash of bright light would cause
A) parasympathetic activation to contract the pupillary sphincter muscles.
B) parasympathetic activation to contract the radial dilator muscles.
C) contraction of the ciliary muscle.
D) sympathetic activation to contract the pupillary sphincter muscles.
E) sympathetic activation to contract the radial dilator muscles.
129) Why do objects viewed underwater with a mask appear closer and larger than they really are?
A) The cornea does not function in water, and the light is not refracted as much.
B) Water is denser than the lens of the eye.
C) Light moves more slowly through the water.
D) Light traveling through the water scatters more than it does when moving through the air.
E) The mask provides additional refraction of light before it reaches the retina.
130) Damage to the fovea of the eye would interfere with the ability to
A) detect objects in the periphery of ones field of vision.
B) focus an image.
C) detect color images.
D) detect the detailed image of objects in the middle of ones field of vision.
E) regulate the amount of light striking the retina.
131) When a rod located in the retina is stimulated by light, the
A) inactive form of retinal associates with bleached opsin.
B) intracellular concentration of cGMP decreases.
C) activity of transducin decreases.
D) cell depolarizes.
E) release of neurotransmitter increases.
132) Put these structures of the visual system in the order that they transmit light to the retina.
1. lens
2. aqueous humor
3. cornea
4. vitreous chamber
A) 2, 3, 4, 1 B) 3, 4, 1, 2 C) 3, 2, 1, 4
1, 2, 3, 4 E) 1, 4, 3, 2
133) Put these structures of the visual system in the order that they transmit visual information from the 1. optic disk
2. visual cortex of the occipital lobe
3. optic chiasm
4. lateral geniculate body of the thalamus
A) 3, 1, 4, 2 B) 3, 1, 2, 4 C) 1, 2, 3, 4 D) 1, 3, 4, 2 E) 1, 3, 2, 4
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
134) With the photoreceptor already stimulated with a moderate light intensity, a(n) (decrease or increase) in light intensity is required to open more CNG channels.
135) Greater visual acuity results from convergence of (fewer or more) numbers of photoreceptors onto retinal ganglion cells. 135)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
136) Which two sensory systems contain a structures called a macula?
A) vestibular and visual
B) gustatory and olfactory
C) visual and somatosensory
D) olfactory and auditory
E) auditory and vestibular
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the symptoms to the problem.
137) Ménière's disease
138) tinnitus
139) central hearing loss
140) sensorineural hearing loss
141) conductive hearing loss
A) problems with structures of the middle ear
B) damage to the cerebral cortex
C) death of hair cells
D) dizziness and nausea
E) ringing in the ears
Match the ganglion cell response to the location of the light stimulus.
142) Light only shines on-center of an off-center visual field.
143) Light only shines on-center of an on-center visual field.
144) Light only shines on-surround of an off-surround visual field.
145) Light only shines on-surround of an on-surround visual field.
146) Diffuse light shines on both center and surround of on-center cell.
147) Diffuse light shines on both center and surround of on-surround cell.
A) inhibited
B) weak response
C) excited
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
148) Distinguish between adequate stimulus, threshold stimulus, and perceptual threshold.
149) Explain labeled line coding and provide a specific example. What exactly is the "label" and the "line" in your example?
150) Explain why calling receptors for noxious stimuli "pain receptors" is inaccurate. What is the more accepted term for these receptors?
151) Describe how lateral inhibition allows for localization of a stimulus.
152) Describe the physiological differences between slow and fast pain.
153) List and define the four major receptor groups.
154) Explain how sensory coding and processing allow the central nervous system to communicate information on the modality, location, intensity, and duration of a stimulus.
155) Discuss the gate control theory of pain modulation.
156) Describe the topographical organization of the somatosensory cortex.
157) List the five taste receptors and what stimulates them, and describe how each of these receptors transduce that stimulus.
158) Describe pitch and loudness and how these properties of sound are processed by the cochlea.
159) Discuss the structure and function of the cochlea.
160) Discuss the structure of the retina, including any distinguishing "regions."
161) List and describe the two types of retinal bipolar cells and how they respond differently to the same neurotransmitter.
162) Provide three reasons for the greater visual acuity at the fovea.
163) While a photoreceptor responds to a single photon of light, a person cannot see a single photon. Explain.
164) Create a concept map explaining the basic structure and function of sensory systems, starting with a receptor cell and ending with the primary sensory cortex. Include the general properties such as receptive fields, stimulus location, and so on. Consider each sensory system in turn and identify exceptions to your basic map, indicating how they are different.
165) Explain how vision is affected by the loss of one eye. Explain how hearing is affected by the loss of one ear. What deficits would people who are blind in one eye or deaf in one ear have? Would loss of half the tongue or half the olfactory epithelium have comparable effects on those systems? Explain.
166) "No brain, no pain" is a cute phrase, but is it true that a brain is required to feel pain? Explain. Brain surgery can be performed on awake patients with anesthesia only to the overlying tissues. Does this indicate that "no brain, no pain" is just a rhyme with no scientific basis? Explain.
167) Explain brain plasticity, and give an advantage and a disadvantage of this process.
168) You work in a paper mill. The smell is horrible every day when you get to work, but by the end of the day, you hardly notice it. Why?
169) Why does there seem to be a link between smell and memory?
170) Describe the action of aspirin and opiates in pain relief. What does your answer suggest about opioids?
171) Based on the structures of the eye and visual pathway, propose several possible causes for blindness.
172) In a recent accident, your favorite uncle lost one of his arms just below the elbow; he had no other injuries. The wound has completely healed, yet he is has pain he claims is coming from a hand that is no longer there. Afraid to confide in his doctor, he asks you if he is going crazy. What should you tell him? What principles are illustrated by this phenomenon?
173) Months after the accident, your amputee uncle's phantom limb pain subsides. One afternoon he is sleeping and you see a fly walk across his upper lip. He wakes up and tells you he just had the funniest feeling. It was as if someone was touching his missing index finger. You decide to experiment with your uncle and you blindfold him. As you touch his cheek he tells you that you are touching his cheek and his missing thumb! As you move around his face you map out his fingers and forearm on his face. Hypothesize how this could be possible.
174) Briefly describe tonic and phasic receptors, and sketch graphs showing any type of stimulus (as a rectangular wave), the receptor potentials generated by each type of receptor, and the resulting action potentials in the neurons that respond to each type of receptor. You do not need to put numbers on your axes; rather you are to demonstrate you understand the relative differences in the responses.
175) Sketch graphs illustrating the electrical response of auditory hair cells and cochlear neurons to sound. You do not need to be precise on the amplitudes or durations; just show you understand the general trend.
Answer Key
Testname: UNTITLED29
1) C
2) B
3) B
4) C
5) D
6) B
7) D
8) C
9) D
10) B
11) A
12) B
13) A
14) A 15) D
16) C
17) B
18) A
19) D
20) E
21) A
22) D
23) C
24) E
25) C
26) C
27) B
28) C
29) A
30) A
31) E
32) D
33) A
34) B
35) C
36) C
37) E
38) A
39) B
40) B
41) A
42) E
43) E
44) E
45) C
46) E
47) B
48) D
49) B
50) A
Answer Key
Testname: UNTITLED29
51) C
52) C
53) C
54) C
55) C
56) D
57) E
58) D
59) D
60) D
61) C
62) C
63) B
64) A
65) D
66) E
67) B
68) A
69) D
70) D
71) C
72) D
73) A
74) B
75) A
76) A
77) B
78) B
79) D
80) E
81) B
82) C
83) A
84) transducer
85) perceptual threshold
86) labeled line coding
87) tonic receptors
88) Phasic receptors
89) nociceptor
90) taste buds
91) dendrites (cilia)
92) cAMP-gated cation channels, increase
93) gustducin, ion channels
94) ATP, serotonin
95) Perilymph
96) potassium, sodium
97) Cristae
98) Endolymph
99) organ of Corti
100) Conductive
Answer Key
Testname: UNTITLED29
101) Sensorineural
102) Bipolar
103) refraction
104) 400 to 750 nm
105) photon
106) Parvocellular (or P), magnocellular (or M)
107) myopia
108) Presbyopia
109) Astigmatism
110) ciliary muscle
111) contracts, more rounded
112) hypothalamus and limbic system
113) ascending
114) reflexive
115) Vanilloid or transient receptor potential (TRP) channels
116) E
117) A
118) C
119) D
120) E
121) C
122) C
123) C
124) A
125) A
126) D
127) E
128) A
129) E
130) D
131) B
132) C
133) D
134) decrease
135) fewer
136) A
137) D
138) E
139) B
140) C
141) A
142) A
143) C
144) A
145) C
146) B
147) B
148) An adequate stimulus is the form of energy to which a receptor is most responsive. A threshold stimulus is the minimum depolarization required to trigger an action potential in a sensory neuron. Perceptual threshold is the minimum stimulus required for a person to be aware that peripheral receptors were stimulated, which can be greater than the threshold stimulus for the sensory neuron.
149) The area of the brain that is stimulated by activity in a particular receptor always perceives the same sensation, regardless of the true nature of the stimulus. For example, a primary auditory cortex neuron interprets as sound both a sound stimulus and an artificial electrical stimulus to a cochlear neuron. In this example, the label is "sound" (the adequate stimulus for the receptor) and the line is all of the neurons involved in the pathway from cochlea to auditory cortex.
150) Pain is a perception, not a type of stimulus. Nociceptors (the correct term) respond to particular types of potentially damaging stimuli, such as abnormally high or low temperatures, or abnormally high pressure or chemical concentrations.
151) Lateral inhibition increases the contrast between receptive fields with the greater extent of activation and the nearby, lesser stimulated, fields. If a stimulus activates three primary neurons with the one in the middle receiving the strongest stimulus, each will activate their secondary neurons. However, the secondary neuron with the strongest stimulus suppresses the response of the other two activated secondary neurons while allowing its own signal to proceed on its pathway without interference. This allows for a greater contrast between the center and sides of the receptive field and a more precise localization of the stimulus.
152) The most notable difference between the two is the timing. Fast pain is sharp and localized. It is rapidly transmitted by myelinated A-δ fibers to the CNS, while slow pain is carried on unmyelinated C fibers. Slow pain is described as duller and more diffuse.
153) Chemoreceptors respond to the binding of chemical ligands.
Mechanoreceptors respond to mechanical energy (pressure, vibration, acceleration: usually by alterations in membrane Thermoreceptors respond to temperature.
Photoreceptors respond to light.
154) Modality, or nature of the stimulus, is indicated by which neurons are activated and where their associated sensory pathways terminate. As each receptor type has an adequate stimulus and labeled line coding ensures that whenever that receptor is activated, the adequate stimulus will be perceived independent of what activated the sensory receptor associated with a particular region of the body. The cerebrum and other brain areas are highly organized into topographic maps of the receptive fields of their sensory receptors, ensuring that location of a stimulus is accurately detected. The number of receptors activated and the frequency of action potentials along the sensory pathway both increase as stimulus intensity is increased. The information on duration depends upon the adaptive properties of the receptor: tonic provide continuous information on a particular parameter whereas phasic provide information that a parameter has changed.
155) In the gate control theory, pain is lessened by an integrated response that reduces the signal sent along the pain pathway. In the region where the noxious/painful stimulus is applied, the C fibers are activated. In this same region of the body, the mechanical rubbing of the site where the pain was initiated activates A-beta fibers to increase the activity the inhibitory interneuron, which reduce the frequency of the pain signal transmitted to the central nervous system.
156) The cells that respond to sensation from a particular body part are organized as a map of the body surface. Thus, cortex cells that respond to sensation from the elbow are located near cells that respond to sensation from the proximal forearm. Furthermore, the number of cortex cells devoted to a sensation is proportional to the sensitivity of that part –there are many more cells for sensation from fingers and lips than from the back or thighs.
157) Sweet (sugar), sour (acid), salty (certain chemical salts), bitter (alkaloid), and umami (savory: glutamate and some nucleotides) are the five sensations. The sweet and umami are type II cells that involve receptor -mediated (T1R) activation of the G protein gustducin and subsequent increase in intracellular calcium, which releases ATP. The other type II cells are bitter, which is similar to those above but uses the T2R receptor to initiate the response. For salty and sour (type I cells), there is direct activation of ion channels to stimulate the release of serotonin. The salty activate the apical ENaC (epithelial sodium channel) to increase the influx of sodium whereas acidic environment alters the gating of ion channels.
158) Pitch is a function of the frequency of sound waves, measured in waves per second (hertz). High frequency waves are interpreted as high-pitched sounds. Loudness is the perception of sound intensity and varies within each individual. The intensity is a function of wave amplitude, measured on a logarithmic scale (units are decibels). The perception of sound frequency is related to the specific hair cell along the basilar membrane that is stimulated: high frequency vibrates the membrane (and thereby hair cells) near the oval window whereas low frequency vibrates hair cell towards the helicotrema. The intensity of sound is communicated by the frequency of action potential that are generated in the cochlear nerve cell (Primary sensory neuron) by the extent of release of neurotransmitter from the hair cell: the more the hair cell depolarizes, the greater the release of neurotransmitter and thereby greater depolarization of the cochlear nerve resulting in a greater frequency of action potentials.
159) The cochlea is made up of the vestibular duct, cochlear duct, and tympanic duct. The vestibular and tympanic ducts are continuous at the helicotrema (found at the tip of the cochlea). Their fluid, perilymph, is similar to plasma. The cochlear duct is filled with endolymph, which is similar in composition to intracellular fluid and is secreted by epithelial cells in the duct. The cochlear duct contains the organ of Corti, which sits on the basilar membrane and is partially covered by the tectorial membrane. These membranes move in response to fluid waves in the vestibular duct and bend the hair cells found in the organ of Corti. When the hair cells move, the stereocilia bend as well and cause the opening of more ion channels and depolarization.
160) The retina consists of layers of cells, with the posterior layer containing the photoreceptors (rods and cones). Photoreceptors synapse onto bipolar cells, which in turn synapse onto an anterior layer of retinal ganglion cells, whose axons comprise the optic nerve. Also present are horizontal cells, which synapse with photoreceptors and bipolar cells, and amacrine cells, which synapse with bipolar and ganglion cells. Cones are sensitive to color and are most concentrated in a spot called the fovea. Another spot is the optic disk or blind spot, where the axons of all ganglion cells merge into the optic nerve, and where there are no photoreceptors.
161) Light-on bipolar cells are inhibited in the dark (due to photoreceptor release of glutamate) and released from this inhibition in the light. Light-off bipolar cells are the opposite. They are activated by the glutamate released in the dark and inhibited in the light. The difference between these cell types is the type of glutamate receptor. ON bipolar cells have metabotropic glutamate receptor (mGluR6) that hyperpolarize the cell in the dark when glutamate release is highest. OFF bipolar cells have an ionotropic glutamate receptors that open channels in the presence of glutamate to depolarize the cell.
162) First, the density of photoreceptive cones is highest at the fovea. Second, only a few photoreceptor cells are associated with a single bipolar cell, which prevents the convergence of information within this region of the retina. Third, light does not have to pass through the layers of cells (amacrine, horizontal, etc) before reaching the photoreceptors within the fovea. Less diffraction of light means greater visual acuity.
163) Stimulation of a receptor is not sufficient to produce sensation that is perceived by the individual. The signals must be enough to allow a photoreceptor to alter neurotransmitter release enough to generate an action potential in the ganglion cell (which a single photon is not). In addition, even if there is a change in release of neurotransmitter, there is processing of visual signals within the retina (amacrine, horizontal and bipolar cells) and in the different brain areas to which that information travels. Thus, not all signals make it to the conscious brain–that is, a single photon is below the perceptual threshold of the visual system.
164) Results will vary. This is discussed in "The Spinal Cord" section of the chapter. Exceptions to the basic plan include: receptor structure is non-neural for most of the special senses, lack of receptive fields for all special senses except vision, lack of routing through the thalamus in the olfactory pathway, lack of stimulus localization by auditory receptors, hydrogen ion or calcium current depolarization in taste cells, oscillating response in auditory hair cells, cessation of ion influx in photoreceptors in response to light.
165) The overlap between the visual fields is required for assessment of depth (three-dimensional assessment). Thus, individuals who have lost an eye would have issues with depth perception. Binaural hearing provides for accurate sound localization. People who have lost hearing in one ear are poorer at sound localization. Comparable losses of sensory tissues for taste or smell would have far less impact on those sensations because there is no similar central comparison of inputs from the two sides.
166) It is true that a brain is required to feel pain. Pain is a perception triggered by potentially damaging stimuli to peripheral receptors. Just as we are deaf or blind if auditory or visual brain areas do not function (or are not present), we feel no pain without brain processing of noxious stimuli. Cutting into the brain without anesthetizing is possible because the brain lacks the receptors that respond to noxious stimuli, thus there are no painful inputs for the brain to process.
167) Brain plasticity is the reorganization of synapses according to how much different parts of the brain are used. An advantage is that people who lose a sensation, such as vision, may develop greater sensation in another area, such as the fingertips of a blind person who uses Braille to read. A disadvantage is that the process is imperfect, and sensations may persist from a body part that is no longer there, such as phantom pain from an amputated limb.
168) Olfactory receptors are phasic. They fire rapidly when they are initially exposed to the smell, but they quickly adapt and cease firing when stimulus (smell) remains constant. They adapt to the new steady state and then turn off so that you don't notice the smell after a little while.
169) Olfactory pathways branch off from the olfactory cortex pathway and lead to parts of the limbic system (amygdala and hippocampus) involved with emotion and memory. It is not clearly understood, but because odors are processed through the limbic system, olfactory memories are created. When the smell is encountered again, it acts as a stimulus for both the olfactory pathway as well as the memory pathway (via the limbic system).
170) Aspirin inhibits prostaglandins (anti-inflammatory) and slows the transmission of pain signals from the site of injury to the brain. Opioids like morphine act on a special class of receptor molecules in the CNS called opioid receptors. Opioids decrease the secretion of neurotransmitter from the primary sensory neurons and post-synaptic inhibition of secondary sensory neurons. The discovery of the mode of action of opioids, that is, the discovery of specific receptors for opioid drugs, led scientists to search for and discover naturally occurring opioids in the CNS–enkephalins and endorphins.
171) There are a large number of structures involved in normal vision; damage to nearly any one of them may result in partial or complete blindness. Starting from the beginning, there must be healthy cornea, lens, retina (including rods and three types of cones, bipolar and ganglion cells, horizontal and amacrine cells), normal pressure in the eye chambers, intact optic nerve, and the remainder of the visual pathway through the visual cortex.
172) Your uncle still has the surviving parts of the sensory pathway that once served the entire arm. This may include the primary sensory neurons, since the severed axons could have regenerated (but even if these cells degenerated, the remainder of the pathway did not). Anything that stimulates the sensory nerve in the stump may cause signals to go to the area of the cerebral cortex that once received inputs only from the hand. Your uncle is not crazy, rather he is experiencing phantom limb pain, which is very real. This phenomenon illustrates labeled line coding and coding of stimulus location.
173) A map of the somatosensory cortex would show that the area corresponding to the phantom hand and forearm is adjacent to the area corresponding to the face. What has happened is the hand cortex has been invaded by the sensory fibers that normally only activate the face area of the cortex. Since the territory for the hand is vacated (not receiving any stimulation), those facial sensory fibers have begun to activate cells there causing the phantom limb sensation.
174) Receptors adapt to stimuli at very different rates that are characteristic of a particular type of adaptation. Tonic receptors change very little over the duration of the stimulus. The extent of the change in membrane potential decreases a bit over time. Tonic receptors provide continuous information about a particular parameter. Phasic receptors adapt very quickly such that they turn off shortly after having been activated. A change in membrane potential over resting is quickly returned back to resting. These types of receptors provide information on regarding change in a parameter (not how much but just that they have changed). Graphs should resemble those in Figure 10 6 in the chapter.
175) Graphs should resemble those in Figure 10.19 in the chapter.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) The two subdivisions of the efferent division of the peripheral nervous system are
A) somatic motor neurons and autonomic neurons.
B) voluntary nervous system and somatic motor neurons.
C) somatic motor neurons and voluntary neurons.
D) the sympathetic and parasympathetic subdivisions.
2) The division of the autonomic nervous system that prepares the body for intense levels of activity and stress is the division.
A) craniosacral
B) intramural
C) parasympathetic
D) sympathetic
E) somatomotor
3) Which statements apply to the parasympathetic division of the nervous system?
A) Its ganglia are on or near their target organs.
B) It is dominant during "resting and digesting" and its ganglia on or near their target organs.
C) It is dominant during "resting and digesting."
D) Epinephrine is the primary neurotransmitter of the parasympathetic division.
E) All of the statements apply.
4) Nicotine enhances the release of in the brain.
A) serotonin
B) glutamate
C) epinephrine
D) acetylcholine
E) dopamine
5) Which area is NOT normally considered to be an autonomic control center?
A) medulla B) hypothalamus C) amygdala D) pons
6) Antagonistic control of efferent output is typical of the division.
A) somatic
B) sensory
C) autonomic
D) somatic and sensory
E) somatic and autonomic
7) The presence of two peripheral efferent neurons in a pathway is typical of the division.
A) somatic
B) sensory
C) autonomic
D) somatic and sensory
E) somatic and autonomic
8) The adrenal medulla is important to the sympathetic branch of the autonomic nervous system because it
A) is a source of catecholamines and is considered a modified sympathetic ganglion.
B) is a source of catecholamines, is considered a modified sympathetic ganglion, and releases epinephrine and norepinephrine directly into the blood.
C) releases epinephrine and norepinephrine directly into the blood.
D) is a source of catecholamines.
E) is considered a modified sympathetic ganglion.
9) Which statement is FALSE?
A) Monoamine oxidase is the main enzyme responsible for the degradation of catecholamines.
B) β1 receptors respond equally well to both epinephrine and norepinephrine.
C) Activation of α receptors are Na+ channels in the membrane.
D) β2 receptors are not innervated by sympathetic neurons, so are more sensitive to epinephrine, delivered through the blood.
10) Which has its cell body in a ganglion?
A) postganglionic neuron
B) preganglionic neuron, postganglionic neuron, and somatic motor neuron
C) preganglionic neuron and postganglionic neuron
D) somatic motor neuron
E) preganglionic neuron
11) Which areas of the brain exert control over the autonomic nervous system?
1. cerebellum
2. hypothalamus
3. pons
4. medulla
5. thalamus
2, 4
12) Which functions are controlled through the autonomic nervous system?
1. blood pressure
2. heart rate
3. water balance
4. temperature regulation
A) 1, 2, 3, 4 B) 1 and 3 C) 1, 2, 3 D) 1 and 2 E) 2, 3, 4
13) Sweat glands contain
A) beta receptors.
B) alpha receptors.
C) cholinergic receptors.
D) All of the answers are correct.
E) None of the answers are correct.
14) Increased parasympathetic stimulation
A) increases sweat.
B) dilates blood vessels in the arms and legs.
C) increases gastric motility.
D) dilates the pupils.
E) increases heart rate.
15) "Dual innervation" refers to an organ receiving
A) nerves from both the brain and the spinal cord.
B) two nerves from the spinal cord.
C) both autonomic and somatomotor nerves.
D) both sympathetic and parasympathetic nerves.
E) None of the answers are correct.
16) The motor end plate is
A) a folded area of muscle cell membrane with ACh receptors clustered at the top of each fold.
B) the same as the neuromuscular junction.
C) the same as the synaptic cleft.
D) a special fibrous matrix whose collagen fibers hold the axon terminal in proper position.
E) formed by the membrane of enlarged axon terminals, that lie on the surface of skeletal muscle cells.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the following with its description.
17) receptor for parasympathetic neurotransmitters
18) receptor for preganglionic neurotransmitters
19) released by all autonomic preganglionic neurons
20) primary sympathetic neurotransmitter
21) receptor for sympathetic neurotransmitters
cholinergic muscarinic receptor
acetylcholine
C) adrenergic receptor
D) norepinephrine
E) cholinergic nicotinic receptor
22) The neural pathway from the spinal cord to the target tissue has two neurons, the preganglionic neuron and the postganglionic neuron.
23) Most preganglionic neurons originate in the thoracic and lumbar regions of the spinal cord.
24) The cell bodies of preganglionic neurons are found either in the brain stem or in the sacral region of the spinal cord.
25) Inside the ganglia are interneurons, which modulate messages.
26) The neurotransmitter acetylcholine is released by neurons at the neuroeffector junction.
27) The ganglia are found in a chain that runs close to the spinal cord or along the descending aorta.
28) The neurotransmitter norepinephrine is released by neurons at the neuroeffector junction.
29) It contains cholinergic neurons.
30) The adrenal medulla is closely associated with this system.
31) On average, one preganglionic neuron synapses with eight or nine postganglionic neurons, each innervating a different target.
32) It is important during stress or emergencies (fight-or-flight).
33) It dominates during resting-and-digesting activities.
A) true for both divisions
B) true only for the parasympathetic division
C) true only for the sympathetic division
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
34) The two types of cholinergic receptors are and 34)
35) Cholinergic receptors respond to the neurotransmitter . 35)
36) Cholinergic nicotinic receptors are found in the of the autonomic division. 36)
37) Cholinergic muscarinic receptors are found at the in the autonomic division. 37)
38) The is the major source of parasympathetic output. 38)
39) are swellings that contain vesicles filled with neurotransmitter. 39)
40) Autonomic neurotransmitters are synthesized in the 40)
41) The two varieties of adrenergic receptors are and . 41)
42) The signal molecule stimulates a stronger responses from alpha receptors. 42)
43) The signal molecule stimulates a stronger response from beta2 receptors. 43)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
44) postganglionic sympathetic neurons secrete onto their target cells.
A) Most, norepinephrine
C) All, acetylcholine
44)
B) Most, acetylcholine
D) All, norepinephrine
45) Epinephrine and norepinephrine that are released from the adrenal glands affect target tissue for a longer period of time than the same substances released from neurons at their peripheral receptors. Why?
A) The epinephrine and norepinephrine from the adrenal glands are released by sympathetic neurons, whereas parasympathetic neurons release these substances at the effector organs.
B) The adrenal gland releases larger amounts of the neurotransmitters than the neurons.
C) There are no enzymes to break down epinephrine and norepinephrine in the blood and very little in peripheral tissues.
D) The effectors are less sensitive to epinephrine and norepinephrine released by the adrenal glands.
E) The hormones released from the adrenal glands bind to different receptors than those released from neurons. 45)
46) If a physiological dose of an experimental drug was administered, and the subject responded to the chemical, which would indicate that this drug is an epinephrine agonist?
A) hypoglycemia (low blood glucose)
B) constriction of respiratory airways
C) decreased sweating
D) increase in fatty acids in the blood
E) decreased heart rate
46)
47) If the results of an experimental drug treatment included pupil dilation, high blood pressure, and high blood glucose, which conclusion would be indicated?
A) It acts on AMPA receptors.
B) It acts on beta adrenergic receptors.
C) It acts on muscarinic receptors.
D) It acts on alpha adrenergic receptors.
E) It acts at the neuromuscular junction.
48) The drug Chantix®, which treats nicotine addiction, is an for the nicotine receptor.
A) antagonist
B) agonist
49) A child is rushed to the hospital after taking one of his grandmother's blood pressure medications. He has a low blood pressure and is also having trouble breathing, with audible wheezing upon exhalation. Which class of drugs did the child most likely take?
A) beta blocker
C) calcium channel blocker
B) ACE inhibitor
D) diuretic
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the response with the type of chemical.
50) pupil dilation
51) increased watery secretions from salivary glands
52) decreased activity in digestive tract
53) fat breakdown
Match the response with the type of chemical.
54) decreases secretion of pancreatic enzymes
55) decreases effects of adrenal catecholamines
56) decreases urination
57) decreases erections
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
58) Explain what is meant by antagonistic control.
59) Draw the divisions of the autonomic nervous system down to their receptors.
60) Describe the different types of adrenergic receptors in the autonomic nervous system. Which neurotransmitter binds to each type? For those that bind more than one neurotransmitter, how does the response to the neurotransmitters compare?
61) Describe the different types of cholinergic receptors in the autonomic nervous system. Which neurotransmitter binds to each type?
62) Which tissues contain both cholinergic and adrenergic receptors, and how does this relate to their autonomic control?
63) Describe the major anatomical differences between the sympathetic and parasympathetic branches.
64) Describe the neurotransmitters secreted by pre- and postganglionic neurons in 11.1 The Autonomic Division. Be sure to specify the types of receptors and synapse location, where relevant, and describe the exceptions.
65) Diagram the events that occur at the neuromuscular junction. Be sure to include the somatic motor neuron, axon terminal, synaptic cleft, synaptic vesicles, motor end plate, and appropriate neurotransmitter(s), ion channel(s), and membrane receptor(s).
66) What steps are necessary to terminate neurotransmitter action? What would happen if these steps failed?
67) Explain the use of the terms fight and flight in describing sympathetic motor responses. How does sympathetic activity explain your increased "jumpiness" when you are home alone at night, watching a horror movie on TV?
68) Anne Frank wrote a diary about the years she and a few others spent in hiding from the Nazis during World War II. These people lived in the upstairs rooms of a shop, accessible only by a hidden stairway; Anne called these quarters the Secret Annex. One day Nazis raided the shop below, but were unsuccessful in locating the hideaways or finding proof of their presence during this particular raid. Clearly hearing what was occurring downstairs, Anne and her cohorts cowered in silence, for they feared being transported to "death camps." Later, Anne wrote that most of the residents of the Secret Annex experienced diarrhea shortly after this close call. Explain this response by their digestive systems.
69) Both alpha-bungarotoxin and curare bind to the same neurotransmitter receptor, but only curare binds reversibly. Which receptor is involved? List some locations for this receptor. Would either toxin be appropriate to use to temporarily paralyze a patient during surgery? Explain your answer. Are all such receptors necessarily affected by a given toxin in the same way? Explain the significance of your answer.
70) Compare and contrast the voltage-gated sodium and potassium channels introduced in Chapter 8, with the acetylcholine receptor/channel. What may be confusing to the beginning physiology student trying to understand the ion specificity of the nicotinic receptor? What type of change in the cell is produced by ion movement through each type of channel?
71) To perform surgery with a minimum of pain for the patient, a patient may be administered a general anesthetic to prevent sensation and consciousness, as well as a drug to prevent reflexive muscle spasms. From what you have learned of motor control, suggest mechanisms by which a drug can prevent muscle contraction. With this drug, what extra measure must be taken to keep the patient alive? Name a drug that can prevent muscle contraction.
72) At the molecular level, what are the effects of nicotine on the nervous system? How are these effects exerted? How are these effects similar to or different from those of curare? How do these effects explain some of the physiological consequences of smoking?
73) In a laboratory experiment, adding curare, which binds to acetylcholine receptors, to the solution around a muscle decreases the size of the end-plate potential. Adding prostigmine, an acetylcholinesterase blocker, increases the size of the end-plate potential. Explain why.
74) Phenelzine is a common MAO inhibitor that has been used to treat depression. However, it is notprescribed as often as other antidepressants due to its effects on the autonomic nervous system. Describe several side effects that may result from taking phenelzine and explain why they might occur.
75) Though you are an attentive parent, you lost track of your child for a few minutes, just long enough for him to wander into the garage and open a package of insecticide that you use to control insects in your garden. You have no idea if any of the poison has been ingested, inhaled, or absorbed through his skin. You take the package away from your child and read under the "caution" section that it is an anticholinesterase. Given that this poison was made for insects, not humans, should you be worried? Explain your answer. What would happen to the child if he has been affected? Explain which type of synapses could be affected. Propose an antidote (it's OK if you don't remember a specific compound, just describe what type of effect may reverse the effects of the insecticide).
76) Control of the neuromuscular junction in this new invertebrate is found to involve dual antagonistic innervation, where one motor neuron secretes an excitatory neurotransmitter and another secretes an inhibitory neurotransmitter onto the muscle. How does this compare to the human neuromuscular junction? Propose three different types of inhibitory receptors/channels that would produce inhibition of the invertebrate muscle, specifying ion and direction of ion flow. For each ion, calculate the equilibrium potential. What similarity do you notice in the equilibrium potentials of the ions involved, and how is that significant? How may inhibition be accomplished in human muscle?
77) Your studies of the neuromuscular junction show that an excitatory neurotransmitter opens a channel permeable to all three cations. Calculate the equilibrium potential for each cation. In which direction will each cation move when the channel is open? Does movement of ions promote muscle depolarization? Explain your answer.
78) Your friend is studying for the MCAT and she has to be very careful to not confuse the two different efferent divisions. To help her study, you create a diagram/flow chart that compares and contrasts the somatic motor division, parasympathetic division, and sympathetic division. Recreate your map here, including all the receptors, target tissues and neurotransmitters.
Answer Key
Testname: UNTITLED30
1) A
2) D
3) B
4) E
5) C
6) C
7) C
8) B
9) C
10) A
11) C
12) A
13) C
14) C
15) D
16) A
17) A
18) E
19) B
20) D
21) C
22) A
23) C
24) B
25) A
26) B
27) C
28) C
29) A
30) C
31) A
32) C
33) B
34) nicotinic, muscarinic
35) acetylcholine
36) autonomic ganglia or ganglia
37) parasympathetic neuroeffector junctions
38) vagus nerve
39) Varicosities
40) axon
41) alpha, beta
42) norepinephrine
43) epinephrine
44) A
45) C
46) D
47) D
48) B
49) A
50) A
51) B
52) A
53) A
54) B
55) A
56) B
57) B
58) For fine-tuned control over the body's internal state, one autonomic branch may have an excitatory effect on a particular organ while the other branch is inhibitory.
59) See Figure 11.9 in the chapter.
60) Alpha 1, alpha 2, beta 1, beta 2, and beta 3 receptors are described in Table 11.2 in the chapter. Most of these receptors are more sensitive to norepinephrine than to epinephrine, but they will all respond to either neurotransmitter. These neurotransmitters are nearly identical structurally, and the response of the target tissue to the binding of either is the same.
61) Cholinergic receptors are either nicotinic or muscarinic; they are distinguishable by the binding of either nicotine or muscarine to the same receptors. Both receptors bind to acetylcholine.
62) A list is provided in Figure 11.5 in the chapter. For most target organs listed, acetylcholine and (nor)epinephrine have opposite effects on the target organ.
63) Sympathetic pathways exit the spinal cord in the thoracic and lumbar regions whereas parasympathetic pathways exit through the cranial and sacral regions. Also, sympathetic ganglia are located near the spinal cord; and therefore, sympathetic pathways typically have short preganglionic fibers and long postganglionic fibers. In contrast, parasympathetic ganglia are located on or near their target tissue; and therefore, parasympathetic pathways have long preganglionic fibers and short postganglionic fibers.
64) Both sympathetic and parasympathetic neurons secrete acetylcholine onto nicotinic receptors within the autonomic ganglion. Postganglionic sympathetic neurons secrete norepinephrine onto adrenergic receptors on target cells at the neuroeffector junction. Postganglionic parasympathetic neurons secrete acetylcholine onto muscarinic receptors on target cells at the neuroeffector junction. Exceptions include sympathetic postganglionic neurons that secrete acetylcholine, and nonadrenergic, noncholinergic neurons that secrete substance P, somatostatin, vasoactive intestinal peptide, adenosine, nitric oxide, or ATP.
65) Variable. See Figure 11.10 in the chapter.
66) Neurotransmitter molecules diffuse away from the cleft, are enzymatically degraded, or are transported into cells around the synapse. Calcium ions are removed from the axon terminal. Failure of these steps prolongs the action of the neurotransmitter. Consequences vary according to the identity of the effector organ. In a skeletal muscle, for example, this can lead to spastic paralysis.
67) When presented with a real or imaginary threat, the sympathetic motor system produces changes that prepare the body to oppose the threat ("fight") or run away from the threat ("flight"). Responses include an increase in heart and respiratory rate, and increased blood flow to cardiac and skeletal muscle. Reading or watching scenes that are threatening to others, even if you could not possibly be at risk, can produce the same sympathetic response in you as if you were actually present in the scene. If the phone rings or there is a knock at the door, you are likely to react to that very quickly, because you are primed for action.
68) Assuming there is no pathogenic or dietary cause, diarrhea probably resulted from the fight-or-flight reaction of the sympathetic nervous system. Digestive tract secretion and motility are inhibited during a sympathetic response. When the threat had passed and the sympathetic nervous system released the digestive targets from inhibition, there may have been a rebound effect in which the parasympathetic division overstimulated the motility of the tract. Increased motility with decreased time for reabsorption of water can result in diarrhea. It is also thought that the sympathetic response actually stimulates the lower gastrointestinal tract though it inhibits the upper tract. This could also account for the effects. Students may need to consult other sources to answer this question correctly.
69) Both of these toxins bind to the nicotinic acetylcholine receptor. This type of receptor is located on skeletal muscle and in autonomic ganglia. For a paralytic during surgery, curare would be appropriate but bungarotoxin would not, because the irreversibility of bungarotoxin binding results in permanent paralysis of skeletal muscles. Bungarotoxin binds to the receptors in skeletal muscle but not to those in autonomic ganglia, illustrating a structural difference in the receptors in these two sites.
70) The voltage-gated sodium channel opens in response to threshold voltage and allows sodium to enter the cell, thereby depolarizing the membrane potential. The potassium channel is also opened by threshold voltage and allows potassium to exit the cell, repolarizing or hyperpolarizing the membrane potential. The nicotinic receptor is a neurotransmitter receptor as well as an ion channel. Because the channel is opened by binding of a chemical, it is a chemically gated channel. This channel is permeable to BOTH sodium and potassium; when the channel opens, sodium diffuses into the cell and potassium diffuses out. The inward positive charge is sufficient to depolarize the skeletal muscle to threshold. Students are often confused by the fact that more than one type of ion moves through the acetylcholine receptor channel, and that the muscle cell is able to depolarize to threshold despite the exit of potassium.
71) From Chapter 9, students should remember that somatic motor control involves the motor areas of the cerebral cortex and the basal nuclei, as well as the cerebellum. A drug that affects activity selectively in those areas could act as a paralytic; however, it is difficult to imagine the nature of the selectivity that would be required, given the use of similar neurotransmitters and receptors throughout the brain. These motor control areas of the brain act upon the spinal motor neurons, which release acetylcholine onto skeletal muscle fibers. These fibers have a type of receptor not found on autonomic targets: the nicotinic acetylcholine receptor. The neuromuscular junction is the single point of control of a skeletal muscle by its motor neuron. A drug that interferes with synaptic transmission at this junction could be a paralytic. Because the respiratory muscles are also controlled by nicotinic neuromuscular junctions, artificial respiration must be provided by the surgical team until the paralytic is cleared from the system. Curare is a drug that works this way–curare binds to the nicotinic ACh receptor, preventing the muscles from being activated by ACh.
72) Nicotine binds to a type of acetylcholine receptor known as the nicotinic receptor; nicotine does not bind to the other type of acetylcholine receptor, the muscarinic receptor. Like acetylcholine, nicotine activates the receptor and produces a postsynaptic response. Nicotinic receptors are located on skeletal muscles and on the postganglionic neurons of both the sympathetic and parasympathetic nervous divisions. Curare also binds to the nicotinic acetylcholine receptor, but it does not activate the receptor; therefore the effect of curare is paralysis of skeletal muscles. Overall, nicotine is a CNS stimulant, suggesting greater stimulation of the sympathetic division than of the parasympathetic division.
73) By binding to acetylcholine receptors, curare prevents the binding of acetylcholine. Curare does not open the receptor channels. An end-plate potential results from the opening of several ACh receptor channels. Thus, if the receptor is blocked, any end-plate potential that is produced would be smaller. Prostigmine blocks the enzyme that stops ACh action by degrading the neurotransmitter. Interfering with this enzyme prolongs the action of ACh, thus more receptor channels open and the end-plate potential is larger.
74) MAO inhibitors prevent the enzymatic breakdown of catecholamines such as norepinephrine. As a result, a higher concentration of norepinephrine remains in the synapse and therefore is able to elicit a longer / stronger response on its target tissues. Consequently, norepinephrine can prolong its activity through sympathetic pathways to increase heart rate and blood pressure, decrease gastric motility causing constipation as well as prevent penile ejaculation leading to sexual dysfunction. This is discussed in "11.1 The Autonomic Division" section of the chapter.
75) Insects have acetylcholine receptors that are similar enough to ours so that yes, you should be worried. Anticholinesterases block the degradation of acetylcholine, thereby prolonging its effects in both muscarinic and nicotinic synapses. If the dose is high enough, spastic paralysis could result, in which muscles contract uncontrollably. If this happens with the respiratory muscles, the victim may die of suffocation. Autonomic effects would also be expected, including sweating and nausea. A chemical such as atropine, which blocks muscarinic receptors, will alleviate some of the symptoms. Oximes (not mentioned in text) block nicotinic receptors and can be administered to counteract nicotinic effects of the poison.
76) The human neuromuscular junction is innervated by only an excitatory neuron. The inhibitory motor neuron in the invertebrate may open a channel to potassium, to chloride, or to both, resulting in hyperpolarization as potassium exits chloride enters.
EK+ = 61 × log 20/420 = -81 mV. ECl- = -61 × log 550/50 = -64 mV.
Both of these equilibrium potentials are negative, indicating that these ions can be useful for inhibition. In humans, inhi muscle activity occurs within the CNS, rather than at the muscle.
77) ENa+ = 61 × log 450/50 = 58 mV. EK+ = 61 × log 20/420 = -81 mV.
EMg++ = 61 × log 60/10 = 47 mV.
Sodium and magnesium will enter the cell, potassium will exit. Exit of potassium opposes depolarization, but presuma will be a net gain in intracellular positive charge sufficient to depolarize the cell.
78) Figure 11.9
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) A flexor is a skeletal muscle whose shortening moves attached bones A) medially.
C) towards one another.
B) laterally.
D) away from one another. 1)
2) Skeletal muscle cells are usually attached to bone by A) fascicles. B) tendons. C) flexors. D) ligaments.
3) The origin is the end of the skeletal muscle that attaches to the A) more stationary bone.
B) more mobile bone. C) ligament.
D) tendon.
4) For antagonistic muscle groups to move a limb, flexor contraction occurs at the same time with A) no changes in the extensor.
C) relaxation of the extensor.
5) The function of transverse tubules is to
2)
3)
4)
B) contraction of the tendon.
D) contraction of the extensor.
A) conduct ATP molecules out of the mitochondria throughout the sarcoplasm.
B) rapidly move action potentials to the interior of the muscle fiber.
C) store Ca2+ ions inside the muscle fiber.
D) ensure a supply of glycogen throughout the muscle sarcoplasm.
6) is made up of multiple globular molecules polymerized to form long chains or filaments.
A) Actin
B) Tropomyosin
C) Myosin
D) Troponin
E) Titin
7) Most of the time, the parallel thick and thin filaments of the myofibrils are connected by that span the space between myosin and actin molecules.
A) crossbridges
B) nebulin molecules
C) sarcomeres
D) calcium ions
E) tropomyosin molecules 7)
8) Striated muscles are so-called because of a repeating pattern of light and dark bands. One repeating unit of the banding pattern is called a
A) crossbridge.
B) myomere.
C) sarcofibril.
D) sarcomere.
E) myofilament. 8)
9) The I band contains
A) myosin only.
C) thin filaments only.
10) The H zone contains
A) thick and thin filaments.
C) thin filaments only.
11) The function of the titin protein is to
B) thick filaments only.
D) thick and thin filaments.
B) actin only.
D) thick filaments only.
A) cover the myosin binding site on the actin molecule.
B) interact with actin during contraction.
C) release calcium during contraction.
D) pull Z lines together during contraction.
E) stabilize the position of the contractile filaments.
12) When a skeletal muscle generates enough force during contraction to shorten,
A) the sarcomere and the I band will shorten.
B) only the sarcomere will shorten.
C) only the A band will shorten.
D) the sarcomere, the A band, and the I band will shorten.
E) only the I band will shorten.
13) The tension generated in a skeletal muscle fiber is directly proportional to the number of
A) low-force crossbridges formed.
B) active sarcomeres.
C) nebulin and titin molecules present.
D) high-force crossbridges formed.
E) thick and thin filaments present.
14) When a skeletal muscle cell contracts and the muscle shortens,
A) the actin molecule swivels during the power stroke.
B) the actin ATPase allows the actin molecule to swivel.
C) some myosin heads are forming crossbridges as others are releasing them.
D) the position of an actin molecule relative to a myosin molecule does not change.
E) myosin heads generate a single power stroke.
15) In order for high-force crossbridges to form in contracting skeletal muscle, calcium must
A) phosphorylate the tropomyosin which moves it.
B) phosphorylate the troponin to move the tropomyosin.
C) bind to tropomyosin which moves the troponin.
D) bind to troponin which moves the tropomyosin.
E) bind to calmodulin to phosphorylate the myosin.
16) Each myosin head has a binding site for
A) calcium only.
B) actin and ATP.
C) actin only.
D) calcium and ATP.
E) ATP only.
17) As ATP binds to the myosin head at the beginning of a muscle contraction cycle, the myosin head immediately
A) tightens its bond to actin.
C) swivels.
B) releases actin.
D) initiates binding with actin.
18) The molecular event that occurs immediately after the power stroke is the
A) hydrolysis of ATP by the myosin head.
B) release of ADP from the myosin.
C) binding of tropomyosin to the myosin.
D) binding of actin to the myosin.
E) release of actin from the myosin head.
19) The hydrolysis of ATP causes myosin to immediately
A) swivel, moving the actin molecule.
B) bind more tightly to the actin (rigor).
C) release from the actin.
D) rotate into a position (cocked) to bind to actin.
E) release ADP.
20) Which would cause the crossbridge to change from a high-force state to a low-force state?
A) energizing the myosin head
B) increasing myosin ATPase activity
C) increasing intracellular calcium
D) decreasing intracellular calcium
E) decreasing myosin ATPase activity
21) The action potential traveling along the t-tubule changes the conformation of the
A) Ca2+ ATPase.
B) dihydropyridine (DHP) receptor (L-type calcium channel).
C) acetylcholine receptor.
D) ryanodine receptor.
22) The binding of acetylcholine to its receptor at the neuromuscular junction causes the opening of a
A) ryanodine receptor.
C) channel for both Na+ and K+ .
B) Na+ channel.
D) Ca2+ channel. 22)
23) The contraction cycle is initiated by the rise in released from the sarcoplasmic reticulum (SR).
A) K+ B) Na+ C) Ca2+
24) The relaxation of skeletal muscle relies on the activity of the , which decreases cytoplasmic calcium concentration.
A) dihydropyridine (DHP) receptor (L-type calcium channel)
B) acetylcholine receptor
C) ryanodine receptor
D) Ca2+-ATPase
23)
24)
25) The brief period of time between the action potential in the muscle and the beginning of contraction is referred to as the
A) depolarization period.
B) relaxation phase.
C) repolarization period.
D) latent period.
E) refractory period.
26) is the backup energy molecule that can be rapidly converted to ATP in active skeletal muscle.
A) Phosphocreatine
C) Glucose
B) Protein
D) Fatty acid
27) During heavy exercise, the ATP requirements of active muscle are likely to be met by metabolism of
A) nucleotides. B) protein.
28) Muscle fatigue likely arises mainly from failure in
A) calcium pumps in the skeletal muscles.
B) excitation-contraction coupling.
C) initiation of contraction by the motor cortex.
D) signal relay from brain to spinal cord.
E) neuromuscular transmission.
C) fatty acids. D) carbohydrates.
29) The cause of skeletal muscle fatigue during extended submaximal exercise is primarily a(n)
A) depletion of K+ stores.
B) increased inorganic phosphate (Pi) concentration.
C) depletion of creatine stores.
D) depletion of glycogen stores.
30) Which is a characteristic of slow-twitch oxidative skeletal muscle fibers?
A) few mitochondria only
B) long contraction duration only
C) long contraction duration and high capillary density
D) long contraction duration, few mitochondria, and high capillary density
E) high capillary density only
31) The speed with which force is developed by skeletal muscles is determined by the A) sarcoplasmic calcium concentration.
B) Ca2+ ATPase activity.
C) myosin ATPase isoform.
D) Ca2+ ATPase activity, myosin ATPase isoform, and sarcoplasmic calcium concentration.
E) Ca2+ ATPase activity and sarcoplasmic calcium concentration.
32) Within a single fiber, the tension developed during a twitch depends upon the
A) length of the thick filament.
B) amplitude of the action potential.
C) length of the sarcomeres prior to contraction.
D) duration of the stimulus.
33) When comparing fused (complete) tetanus with unfused (incomplete) tetanus, which is true?
A) Complete tetanus involves development of maximum tension.
B) Complete tetanus would occur when there is more time between twitch contractions.
C) Complete tetanus involves some relaxation between twitches.
D) Complete tetanus occurs at a lower frequency of stimulation than unfused tetanus.
34) A motor unit consists of
A) one axon terminal branch and the myofibrils it controls.
B) one neuron and all the skeletal muscle fibers it controls.
C) one skeletal muscle fiber and the neuron that controls that fiber.
D) one skeletal muscle fiber and all the neurons that control that fiber.
35) Motor units that control skeletal muscles involved with fine motor movements (eye muscles or the hands) have muscle fibers than motor units that control more gross movements (gastrocnemius muscle of the lower leg).
A) fewer B) more C) the same number of
36) Which statement about motor units and their activation is FALSE?
A) At its peak intensity, a contractile stimulus will activate muscle fibers that are easily fatigued.
B) A motor unit in muscles of gross movement can have thousands of muscle cells.
C) The metabolic capacity of muscle fibers within a motor unit can be altered.
D) All muscle fibers in a single motor unit are of the same fiber type.
E) A weak contractile stimulus activates fast-twitch motor units.
37) Which fibers generate more force?
A) slow-twitch fibers
38) Which fibers fatigue sooner?
B) fast-twitch fibers
A) fast-twitch fibers B) slow-twitch fibers
39) The nervous system avoids muscle fatigue during submaximal contraction by
A) always recruiting slow-twitch motor units.
B) always recruiting fast-twitch motor units.
C) asynchronous recruitment.
D) synchronous recruitment.
40) A contraction that generates enough force to move a load is known as , whereas one that generates force that equals the load is known as .
A) isometric, eccentric
B) isotonic, isometric
C) isotropic, isometric
D) isotonic, eccentric
E) isometric, isotonic
41) Before the entire muscle can change length, the force generated by the muscle must stretch the
A) series elastic elements.
B) parallel elastic elements.
C) eccentric contractile elements. D) contractile elements.
42) In the lever system that characterizes the interaction between bones and muscle, the bones act as the whereas the joints form the
A) lever, pulleys
C) lever, fulcrums
B) fulcrum, pulleys
D) fulcrum, levers
43) In order for the bicep muscle to shorten, the force applied by the muscle must be the load applied at the hand.
A) less than
B) equal to C) greater than
44) Compared to skeletal muscle, contraction of smooth muscle cells is
A) only a slower response to a stimulus.
B) a slower response to a stimulus and sustained without fatigue.
C) only controlled by the somatic nervous system.
D) a slower response to a stimulus, sustained without fatigue, and controlled by the somatic nervous system.
E) only sustained without fatigue.
45) Smooth muscle cells do not have which protein(s)?
A) troponin and tropomyosin
B) tropomyosin only
C) troponin only
D) myosin only
E) actin only
46) Which is NOT a property of single-unit smooth muscles?
A) Only some of the smooth muscle cells are associated with autonomic neuron axon terminals.
B) Smooth muscle cells are connected by gap junctions.
C) Their contraction occurs in a coordinated manner.
D) Electrical responses travel directly between cells.
E) Each cell functions independent of its neighbor.
47) This protein is activated by the Ca2+-calmodulin complex to phosphorylate the myosin light chain protein.
A) myosin light chain kinase
C) tropomyosin
B) myosin light chain phosphatase
D) myosin heavy chain 47)
48) The calcium release channel in the smooth muscle sarcoplasmic reticulum that is opened by increases in phospholipase C activity is the
A) ryanodine receptor.
B) dihydropyridine (DHP) receptor.
C) voltage-gated Ca2+ channel.
D) inositol trisphosphate (IP3) receptor channel.
E) Ca2+-ATPase. 48)
49) A change in smooth muscle cell contraction in the absence of a change in electrical potential of the cells is described as a(n)
A) pacemaker potential.
C) electromechanical coupling.
B) slow wave potential.
D) pharmacomechanical coupling.
50) Which is NOT a correct comparison of cardiac myocytes to other muscle cell types?
A) Like some smooth muscle cells, cardiac myocytes are electrically coupled.
B) Like smooth muscle cells, cardiac muscle is under hormonal control.
C) Like smooth muscle cells, some cardiac myocytes have pacemaker potentials.
D) Like skeletal muscle, contraction of cardiac muscle is under autonomic nervous control.
E) Like skeletal muscle cells, actin and myosin are organized into sarcomeres.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the structures with the accurate description.
51) inward extensions of the muscle cell membrane
52) highly-organized bundles of contractile proteins within a skeletal muscle cell
53) a single muscle cell
54) the muscle cell membrane
55) a bundle of adjacent muscle cells
Match from the following list.
56) The structures that serve as the attachment site for the thin filaments and mark the boundaries for one sarcomere.
57) The letter assigned to this structure stands for the German word for middle; it is the attachment site for the thick filaments.
58) The lightest color bands of the sarcomere, made up only of thin filaments.
muscle fiber
sarcolemma
fascicle
t-tubules
59) The band with the most overlap between thick and thin filaments, which unevenly scatters light leading to its' dark appearance. A) I band
B) Z disk C) M line D) A band
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
60) What are the three types of muscle tissues in the human body? What are the two common functions of muscles?
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
61) Groups of adjacent fibers bundled together into units are called . These bundles are surrounded by the proteins and elastin and which deliver nutrients to the muscle cells.
62) The thick filament of the myofibril is made up of molecules whereas is a protein that makes up the thin filaments. 62)
63) The t-tubule membrane contains receptors that are and therefore respond to action potentials. This receptor is mechanically linked to receptors in the adjacent sarcoplasmic reticulum.
64) In order to contract and relax, muscle cells require energy in the form of . The immediate backup energy source is that requires the enzyme . 64)
65) Calcium, released by the sarcoplasmic reticulum, binds to to move , which allows to bind with myosin. 65)
66) The heavy chain of myosin contains two important regions: the first acts as to convert energy into movement whereas the second binds to 66)
67) As a muscle cell undergoes an eccentric contraction, sarcomere length will as the length of the A band 67)
68) Fatigue that occurs in response to extended submaximal exertion is usually due to depletion of stores whereas fatigue in short-duration maximal exertion involves increased or decreased release. 68)
69) Decreases in muscle force generation at lengths different from optimal are a result of . 69)
70) In fast-twitch oxidative-glycolytic fibers, their rapid increases in force rely on the activity where rapid relaxation requires activity. 70)
71) Asynchronous activation of motor units is important because it functions to 71)
72) In comparison to skeletal muscle, smooth muscle cells function over a range of and exhibit a speed of contraction that is than skeletal muscle.
72)
73) Smooth muscle fibers can sustain a contraction without fatigue by allowing dephosphorylated myosin to remain attached to actin in what is called the 73)
74) In smooth muscle cells, Ca2+ binds to which activates the enzyme to phosphorylate myosin and increase force. 74)
75) Store-operated calcium channels open in response to 75)
76) The gap junctions in cardiac muscle are part of specialized cell junctions that are localized to the 76)
77) A(n) contraction describes the opening of stretch-activated channels in smooth muscle cells in response to a distortion of the cell membrane that is commonly observed in . 77)
78) and are striated muscles. Why are these muscles classified as striated muscles? 78)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
79) Put these events in the correct chronological sequence:
1. End-plate potentials trigger action potentials.
2. Transverse tubules bring potentials into the interior of the cell.
3. Acetylcholine binds to receptors on the motor end plate.
4. Ca2+ is released from the sarcoplasmic reticulum.
A) 3, 1, 4, 2 B) 2, 1, 4, 3 C) 1, 2, 3, 4
80) After death, when metabolism stops, in which step of the contractile cycle must skeletal muscles remain?
A) a weak binding state
B) It depends on what part of the contractile cycle they were in at the time of death.
C) the power stoke phase
D) the rigor state 80)
81) The factor(s) that determine the duration of a twitch in various types of fibers is the speed of the
A) hydrolysis of ATP only.
B) removal of Ca2+ ions from the sarcoplasm and hydrolysis of ATP and movement of Na+ across their membranes.
C) removal of Ca2+ ions from the sarcoplasm only.
D) movement of Na+ across their membranes only.
E) removal of Ca2+ ions from the sarcoplasm and hydrolysis of ATP. 81)
82) Skeletal muscle fibers with the greatest endurance rely on for energy.
A) oxidative phosphorylation
C) ketone body degradation
B) anaerobic glycolysis
D) lactic acid accumulation 82)
83) The force generated by a single muscle fiber can be increased by increasing
A) muscle length beyond optimal only.
B) frequency of action potentials and increasing muscle length beyond optimal only.
C) frequency of action potentials only.
D) the asynchrony of recruitment only.
84) Put these myofibers in the order they would be recruited as the body moves from a weak to a strong stimulus:
1. glycolytic fast-twitch fibers
2. fatigue-resistant oxidative fast-twitch fibers
3. fatigue-resistant slow-twitch fibers
A) 3, 1, 2 B) 2, 3, 1 C) 1, 3, 2 D) 3, 2, 1 E) 1, 2, 3
83)
85) An important difference between single-unit and multiunit smooth muscle is the
A) numerous gap junctions in single-unit smooth muscle, which allow many cells to work together as a sheet.
B) closely controlled individual fibers in single-unit smooth muscle to allow fine control and graded contractions by selective activation.
C) longer actin and myosin filaments in multiunit smooth muscle, which allow coordination of contraction.
D) ability of single-unit fibers to change into multiunit fibers when needed.
86) Relative to skeletal muscle, smooth muscle
A) uses less energy to generate a given amount of force, can sustain contractile force without fatigue and uses calcium from the sarcoplasmic reticulum and extracellular space.
B) uses less energy to generate a given amount of force and can sustain contractile force without fatigue.
C) only uses less energy to generate a given amount of force.
D) only can sustain contractile force without fatigue.
E) only uses calcium from the sarcoplasmic reticulum and extracellular space.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
87) Draw and label a relaxed sarcomere, then draw the same sarcomere in a contracted state. The myofilaments may be represented as simple lines.
88) List and explain the functions of the regulatory molecules in a sarcomere, specifying how the on and off positions are controlled and its impact on the crossbridges formed.
89) Factors playing a role in fatigue can be classified into two categories. Define those two categories and provide an example of each.
90) Compare and contrast the structural and functional differences between single-unit and multi-unit smooth muscle fibers, particularly in regard to their ability to vary their force of contraction.
91) Briefly compare and contrast the structure and behavior of cardiac, smooth, and skeletal muscles.
92) Outline and explain the cellular event that affects the force generated by smooth muscle cells. What are the initiating events, and how do these events affect force production by the smooth muscle cell? How can this process be activated without changes in membrane potential?
93) Explain the events leading up to a skeletal muscle twitch, starting with the arrival of neurotransmitter in the neuromuscular junction.
94) Describe the process of relaxation of a skeletal muscle fiber.
95) List, compare, and contrast the types of skeletal muscle fibers based on their speed of contraction and resistance to fatigue. Give examples of where each type might be found, and why it is advantageous for each type to occur there.
96) Define and explain the differences between slow wave potentials and pacemaker potentials in smooth muscle cells.
97) Define and explain the difference between isotonic, isometric and eccentric contractions and give an example of a specific movement for each. What is the role of series elastic elements in muscle contraction?
98) Myasthenia gravis is a disease characterized by reduction in the number of acetylcholine receptors on skeletal muscles. Which physiological process would be affected? What would someone afflicted by this disease experience? How may this disease be treated?
99) A construction worker entered the emergency room after an accident in which his leg was crushed by falling beams. The color of the urine sample is noticeably reddish brown. Assuming that color is related to the accident, what molecule could have been released from the damaged muscle cells that colored the urine? What is the function of this molecule?
100) Describe the muscle condition called tetanus. Is this a normal or a pathological event? If it is normal, what is the function? If it is pathological, what is the cause? The bacterium Clostridium tetani causes a disease called tetanus or lockjaw; you may have been vaccinated against tetanus, especially if you ever had hospital treatment for a skin wound. Speculate on whether or not the name of this disease is related to the muscle condition and why the disease can be fatal.
101) You and your lab partner use a living nerve and muscle preparation to study muscle contraction. When you stimulate the nerve electrically, the muscle contracts; why? When you turn off the stimulator but add a high concentration of caffeine to the fluid surrounding the tissues, the muscle contracts; why (speculate on possible sites/mechanisms of action)? When curare (which blocks neuromuscular transmission) is added with caffeine, contraction occurs; why (speculate, and how does this alter your previous answer)? Can you identify a single site of action from this information? If not, what additional experiment would narrow your choices?
102) A certain drug is known to block monovalent cation channels. This drug is used as a "muscle relaxer." Would it affect both smooth and skeletal muscles or only skeletal muscles? Defend your answer.
103) The interaction between Ca2+ and calmodulin in smooth muscle cells has been described as a second messenger system. Develop an argument to support this position, using another second messenger system you have studied for comparison.
104) Smooth muscle cells of blood vessels are described as integrating centers. Outline the various inputs that affect smooth muscle cells and how those are integrated.
105) Sketch a graph of the length-tension relationship in a contracting skeletal muscle, and explain its shape in terms of events in the sarcomere.
106) The graph below was generated by students in a physiology lab. The top trace (myogram) shows contraction for bottom (EMG) shows the electrical stimulus. On the graph, label a muscle twitch. What property of muscle is bei tested here? What caused the increase in force (and subsequent decrease)?
Answer Key
Testname: UNTITLED31
1) C
2) B
3) A
4) C
5) B
6) A
7) A
8) D
9) C
10) D
11) E
12) A
13) D
14) C 15) D
16) B
17) B
18) B
19) D
20) A
21) B
22) C
23) C
24) D
25) D
26) A
27) D
28) B
29) D
30) C
31) C
32) C
33) A
34) B
35) A
36) E
37) B
38) A
39) C
40) B
41) A
42) C
43) C
44) B
45) C
46) E
47) A
48) D
49) D
50) D
Answer Key
Testname: UNTITLED31
51) D
52) E
53) A
54) B
55) C
56) B
57) C
58) A
59) D
60) Three types of tissues are skeletal muscle, cardiac muscle, and smooth muscle. The two common functions are to generate motion and to generate force.
61) fascicles, collagen, blood vessels
62) myosin, actin
63) dihydropyridine (DHP) or L-type calcium channel, voltage-sensing, ryanodine (RyR) or calcium release channel
64) ATP, phosphocreatine, creatine kinase
65) troponin C, tropomyosin, actin
66) ATPase, actin
67) increase, does not change (remains constant)
68) glycogen, inorganic phosphate (Pi), calcium (Ca2+)
69) decreases in crossbridge formation
70) myosin ATPase, Ca2+-ATPase
71) avoid fatigue
72) lengths, slower
73) latch state
74) calmodulin, myosin light chain kinase (MLCK)
75) depleted intracellular stores of calcium (when SR Ca2+ stores decrease)
76) intercalated disks
77) myogenic, blood vessels
78) Skeletal, cardiac muscle; they are called this because of their alternating light and dark bands. (See Figures 12.1a and 12.1b in the chapter.)
79) E
80) D
81) C
82) A
83) C
84) D
85) A
86) A
87) Sketch should resemble Figure 12.5 in the chapter.
88) Troponin and tropomyosin and the primary regulatory proteins. Tropomyosin wraps around the actin of the thin filament to restrict access of the myosin to its binding site on the actin molecule. When intracellular calcium concentration is low such that troponin is not bound by calcium (resting muscle), the tropomyosin is in the off position and myosin is weakly bound to actin (low force crossbridge). When muscle is stimulated, the increasing calcium binds to the troponin (C subunit) to shift the tropomyosin into the on position. In the on position, the crossbridges that are formed are high force.
89) Central fatigue, peripheral fatigue. Central fatigue arises in the central nervous system. Peripheral fatigue arises anywhere between the neuromuscular junction and the contractile elements of the muscle. Examples of central fatigue: subjective feeling of tiredness and a desire to cease activity. Example of peripheral fatigue is depletion of muscle glycogen stores, increases in inorganic phosphate concentration, or ion imbalance. See Figure 12.13 in the chapter.
90) Single-unit characteristics: all smooth muscle cells contract as a unit due to presence of gap junctions; found in walls of hollow organs; strength depends upon amount of calcium that enters the cell. Multi-unit characteristics: each smooth muscle cell is controlled independently; found in few locations, including iris and ciliary body; strength depends upon fiber recruitment.
91) See Table 12.3 in the chapter.
92) See Figure 12.26 in the chapter. Describe how myosin light chain kinase and myosin light chain phosphatase are regulated as it is the interaction between two proteins that determines the extent of phosphorylation of the myosin light chain and thereby the amount of force generated by the smooth muscle cells. While responses in smooth muscle cells can be initiated by changes in membrane potential that increase intracellular calcium by altering calcium channel activity (electromechanical coupling) in the cell membrane, receptors that are activated by chemical signals can also stimulate the release of calcium from the sarcoplasmic reticulum without changes in membrane potential that can also affect force of contraction of smooth muscle cells (pharmacomechanical coupling).
93) See Figure 12.10 in the chapter. Acetylcholine binds to its receptor (nicotinic cholinergic) on the skeletal muscle cell membrane. This increases in flux of cations across the membrane of which the influx of Na is greater than the efflux of K, which causes the membrane to depolarize (end-plate potential). This depolarization activates the voltage gated Na channels responsible for an action potential and the action potential travels along the sarcolemma. In addition to the sarcolemma, the action potential travels along the T-tubule causing change in the L-type Ca channel (dihydropyridine receptor) that is linked to a ryanodine receptor in the sarcoplasmic reticulum. This opens the ryanodine receptor causing calcium to diffuse out of the sarcoplasmic reticulum. The calcium binds to troponin and moves the tropomyosin out of the way such that a high-force crossbridge can form between actin and myosin. The myosin head is then able to undergo its power stroke and force is generated.
94) Relaxation is an active process, resulting from loss of acetylcholine from the receptors as ACh is broken down and there is no further release. This allows the muscle cell to repolarize, which stops the release of calcium from the sarcoplasmic reticulum (SR). The pumping of calcium back into the SR causes the troponin to move the tropomyosin into a position that it allows only a low-force crossbridge to form and the cell to relax.
95) See Table 12.2 in the chapter.
96) See Figure 12.28 in the chapter. Slow wave potential describes the cyclic depolarization of smooth muscle cells that can lead to the generation of action potentials. When that depolarization is above threshold, action potentials are generated at a level consistent with the magnitude of that depolarization. For pacemaker potentials, some smooth muscle cells have oscillating membrane potentials that always reach threshold and generate an action potential. This causes the generation of a regular rhythm of action potentials within these cells.
97) Isotonic means same tension, that is, a type of muscle contraction that involves movement with a constant tension or force. An example is what the biceps brachii muscle does when flexing the elbow–once tension increases enough to move the weight of the forearm, the forearm moves steadily without further increase in tension. Isometric means same length, that is, a type of muscle contraction that involves development of force without the muscle actually shortening and moving a load. An example is what the biceps brachii muscle does when trying to hold an object without changing length. Tension is exactly equal to load, which is why length does not change. In an eccentric muscle contraction, the load applied to the muscle is more than the tension that muscle can generate causing the muscle to lengthen. For example, the biceps brachii muscle is flexed and you have in your hands a weight that is greater than you can lift. Thus, you slowly allow the biceps muscle to lengthen resisting movement of that heavy weight. The series elastic elements are composed of the connective tissue of the tendons and that, which is between muscle cells. Before force would be detected at the tendon (latent period), some shortening of the contractile elements occurs that pulls on the series elastic elements. Once stretched, the force can now be detected at the tendon.
98) Neuromuscular transmission would be affected, and therefore excitation-contraction coupling. Skeletal muscles would be less excitable, and muscle tone and strength would decrease. A treatment that could increase the amount of acetylcholine released or prolong its action, such as a treatment interfering with acetylcholine breakdown, would offer some improvement.
99) The molecule is likely to be the pigment myoglobin. This molecule binds to oxygen in muscle cells to supplement the oxygen supplied by the blood.
100) Tetanus is a state of maintained contraction that occurs as a result of increased frequency of stimulation by the nerve that does not allow enough time between twitches for the muscle to relax. Tetanus is a normal event, which allows a muscle to develop its maximal force. The bacterial disease results in maintained contraction that is similar in charter to the tetanus that can result from high frequency muscle stimulation. The disease is fatal if respiratory muscles are unable to relax because then breathing would stop.
101) The applied electrical current opens voltage-gated ion channels in the nerve, causing an action potential, which leads to the release of the neurotransmitter acetylcholine to stimulate an action potential in the skeletal muscle. This activates excitation contraction coupling to increase intracellular calcium and thereby allow actin and myosin to interact. If the muscle contracts to caffeine, then it must have done so by increasing intracellular calcium as that is required to generate force. How caffeine increases intracellular calcium cannot be determined yet. However, since the addition of curare does not affect contraction, then caffeine must be acting directly on the skeletal muscle as the affect of acetylcholine on the muscle cell is blocked by curare. Whether caffeine can increase intracellular calcium by stimulating an action potential or some other way is not clear from the experiments. To determine whether the action potential is required, tetrodotoxin could be used to block the action potential. In this case, the cell would still be generating force which indicates that the site of action of caffeine is somewhere between the L type calcium channel and the release of calcium from the sarcoplasmic reticulum (caffeine opens ryanodine receptor in the sarcoplasmic reticulum).
102) Skeletal muscle relies on monovalent cation channels for the generation of action potentials to trigger contraction, whereas smooth muscle cells have more "routes" available to trigger contraction. Blocking one route would not be sufficient to cause relaxation; hence, this drug would be more likely to be effective on skeletal muscle.
103) Ca2+ forms a complex with calmodulin. This complex activates myosin light chain kinase, which in turn phosphorylates the myosin light chain allowing the myosin to form a crossbridge with actin, triggering the contraction cycle. The second messengers cGMP and cAMP also lead to the phosphorylation of proteins to affect cell activity.
104) Myogenic responses, autonomic neurotransmitters, and paracrine mediators all affect smooth muscle cells. Myogenic responses involve alterations in stretch of the overlying smooth muscle cells in blood vessels when the pressure inside of them is altered. The autonomic neurotransmitters bind to receptors that affect second messenger signaling through intracellular inositol trisphosphate (IP3) or cAMP concentration to increase or decrease (respectively) the force generation by the smooth muscle cells. Paracrine and endocrine mediators also bind to receptors on smooth muscle cells to alter second messenger signaling. In the end, it is the balance of myosin light chain kinase and myosin light chain phosphatase activity that determines how much force a smooth muscle generates and thereby how it will respond to the various signals that it is receiving.
105) Sketch should resemble Figure 12.15 in the chapter. At optimal length, the extent of overlap between thick and thin filaments at onset of contraction is the greatest. Thus, the number of actin and myosin crossbridges is the greatest. On either side of optimum, the extent of interaction between actin and myosin is reduced thereby decreasing the number of crossbridges that can form, which reduces the force of contraction of skeletal muscle cells.
106) The clearest single twitches are the first few and last few peaks on the myogram. The muscle is being stimulated at an increasing rate (frequency), as evidenced by the decreasing time between subsequent stimulus pulses. This caused fusion of the twitches (summation), producing partial then complete tetanus, as well as an increase in peak force produced. Though the stimulus is maintained, the peak force starts to fall as the muscle fatigues. The students then decreased the stimulus frequency, allowing recovery from fatigue.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) The target in a reflex is the
A) muscle or gland.
B) afferent neuron.
C) efferent neuron.
D) control center.
E) sensory receptor.
2) A polysynaptic reflex has at least in the reflex pathway.
A) two neurons
B) three neurons
C) one synapse
D) two synapses
E) two synapses and three neurons
3) Identify the FALSE statement.
A) All reflexes require input from the brain.
B) Adipose tissue is controlled by autonomic efferent neurons.
C) Proprioceptors detect limb position and movement.
D) Muscle spindles are stretch receptors.
E) Some reflexes are genetically determined. 3)
4) Which reflex is NOT controlled by the brain stem?
A) salivating
B) vomiting
C) sneezing
D) urination
E) swallowing
5) Which about autonomic reflexes is FALSE?
A) Integrating centers for autonomic reflexes in the brain include the hypothalamus, brain stem, and limbic system.
B) Autonomic reflexes are all monosynaptic, with their synapse in the central nervous system.
C) Many autonomic reflexes are characterized by tonic activity, a continuous stream of action potentials.
D) Vomiting, sneezing, and coughing are all examples of autonomic reflexes.
6) The sensory fibers of the muscle spindles synapse onto
A) gamma motor neurons.
C) alpha motor neurons.
B) joint receptors.
D) Golgi tendon organs.
7) The reflex that prevents damage from overstretching is the
A) tendon reflex.
B) crossed extensor reflex.
C) reciprocal reflex.
D) flexion reflex.
E) stretch reflex.
8) The flexion reflex
A) prevents a muscle from overstretching.
B) makes adjustments in other parts of the body in response to a particular stimulus.
C) prevents a muscle from generating damaging tension.
D) is an example of a monosynaptic reflex.
E) moves a limb away from a painful stimulus.
9) The reflex that complements a withdrawal reflex by making compensatory adjustments on the opposite side of the body receiving the stimulus is the
A) tendon reflex.
B) stretch reflex.
C) reciprocal reflex.
D) crossed extensor reflex.
E) flexion reflex.
10) It is the middle of winter and you walk over an icy patch and lose your balance. As you begin to fall, you react by extending your arms to catch yourself. In this instance, what type of reflex is occurring?
A) tendon reflex
B) reciprocal reflex
C) flexion reflex
D) crossed extensor reflex
E) stretch reflex
11) Spinal interneurons prevent muscle antagonists from interfering with an intended movement by
A) the process of reciprocal inhibition.
C) initiating a crossed extensor reflex.
B) initiating a stretch reflex.
D) initiating a tendon reflex.
12) The "normal" contractile fibers of the muscle are also called the A) intrafusal fibers. B) extrafusal fibers. C) muscle spindle fibers. 12)
13) Motor neurons are sometimes inhibited by
A) joint receptors. B) muscle spindle organs. C) Golgi tendon organs. 13)
14) Most reflex movements are integrated by
A) the brain.
B) proprioceptors.
C) central pattern generators.
D) effectors.
E) the spinal cord.
15) Which class of movement can be considered a combination of the other two?
A) rhythmic B) reflex C) voluntary 15)
16) Many reflexes are regulated by
A) positive feedback.
B) negative feedback.
C) ganglia.
D) the brain.
E) the spinal cord.
17) Interneurons of the corticospinal tract synapse onto A) interneurons of central pattern generators.
B) somatic efferent neurons.
C) visceral efferent neurons.
18) The structure whose abnormal function is associated with Parkinson's disease is the A) cerebellum.
B) skeletal muscle.
C) spinal cord.
D) primary motor cortex.
E) basal ganglia.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the type of reflex to its description.
19) integrated in the brain
20) several neurons involved in a pathway; can be complex
21) involves skeletal muscles
22) reflexes that one is born with; genetically determined
23) integrated in the spinal cord, often modulated by the brain
24) an example would be slowing or speeding the heart and other internal organs that are not consciously controlled
25) our experiences tell us how to behave; bracing yourself in anticipation would be an example
Match the structure to its description.
26) maintain muscle tone at rest through tonic activity
27) have afferent neurons that bring information to the CNS
28) excite both alpha and gamma motor neurons
29) found at the junction of tendons and muscle fibers
30) have gamma motor neurons that innervate internal fibers
31) eventually synapses with alpha motor neurons that innervate extrafusal muscle fibers
both
muscle spindles C) Golgi tendon organs
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
32) The motor neurons that innervate the normal contractile fibers of the muscle are the 32)
33) motor neurons are associated with intrafusal muscle fibers. 33)
34) The tension maintained in a muscle at rest is known as 34)
35) In order to flex a limb, the extensors must first be relaxed and vice versa. This is done by a process called 35)
36) Relaxation of skeletal muscle results from input by the somatic motor neuron. 36)
37) Rhythmic movements, such as breathing or walking, are controlled by networks of neurons in the central nervous system called 37)
38) monitor the position of skeletal muscles and joints. 38)
39) Autonomic reflexes are also called reflexes. 39)
40) reflexes involve skeletal muscles. 40)
41) In a reflex, a sensory neuron synapses directly on a motor neuron. 41)
42) A reflex has at least one interneuron placed between the sensory and motor neuron. 42)
43) Many reflexes are regulated by 43)
44) The is a group of interneurons that run from the motor cortex to the spinal cord. 44)
45) allows the body to anticipate a stimulus and begin the response, whereas negative feedback results in the of a response. 45)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
46) The control of voluntary movement can be divided into what three steps?
47) A muscle at rest exhibits no tension. Is this statement true or false? Explain your answer.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
48) After stretching an intrafusal fiber, the next event is
A) an increase in action potentials along the associated sensory neuron.
B) decreased sensitivity to stretching.
C) a decrease in muscle tension.
D) a decrease in muscle tone.
E) All of the answers are correct. 48)
49) When there is a resistance to stretch produced by a given limb muscle,
A) there is a decrease in the amount of force generated by extrafusal muscle fibers.
B) the muscle involved in the movement immediately shortens when stimulated.
C) intrafusal fibers receive fewer action potentials from the gamma motor neurons.
D) gamma motor neurons are inhibited by higher brain centers.
E) muscle tone is increased and more motor units are recruited to the contraction.
50) Ten-year-old Tina falls while climbing a tree and lands on her back. Her frightened parents take her to the local emergency room where she is examined. Her knee jerk reflex is normal. These results suggest that
A) Tina has injured one of her ascending nerve tracts.
B) Tina has a spinal injury in the lumbar region.
C) Tina has injured one of her descending nerve tracts.
D) Tina suffered no damage to her spinal cord.
E) Tina has a spinal injury in the cervical region.
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
51) Muscle spindles are receptors and provides information, whereas Golgi tendon organs respond primarily to and cause a reflex. 51)
52) The collection of pathways controlling a single joint is known as . The simplest reflex in this collection of pathways is the , which involves only two neurons: neuron from the and the motor neuron to the muscle.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
53) Are relaxation of a muscle and inhibition of a muscle the same thing? Explain your answer.
52)
54) What are the three levels of nervous system that control movement? Briefly describe their roles.
55) List three ways that neural reflex pathways can be classified. Name one of the reflexes in each category. What additional information may be gained from the name of the reflex? Name a specific reflex and identify its classification in all of the categories you listed.
56) Design a concept map that shows the types of reflexes, the basis for their classification, and their functions.
57) How does the stretch reflex protect a muscle?
58) Name the steps of a reflex pathway, and describe generally how a reflex works.
59) Compare and contrast the structures and functions of the Golgi tendon organ and the muscle spindle.
60) You are studying for your physiology test with your lab partner. She insists that the purpose of the knee jerk reflex is to test for neural or muscular damage. State whether or not you agree with her, and why.
61) Explain alpha-gamma coactivation.
62) Compare and contrast the three categories of movement described in the text and give an example of each.
63) Make Draw a map of the integration of muscle reflexes. Include the following terms: brain stem, cerebellum, cerebral cortex, feedback, muscle contraction and movement, sensory receptors, signal, spinal cord, and thalamus.
64) Make a map of the following terms: alpha motor neurons, CNS, contractile fibers, extrafusual muscle fibers, Golgi tendon organs, integrating center, joint receptors, muscle spindles, proprioreceptors, sensory neurons, sensory receptors and somatic motor neurons.
65) Draw a monosynaptic reflex and a polysynaptic reflex. Label each part of the reflex pathway. Briefly explain how the two reflexes differ.
66) List and describe the three categories of movement. Explain why these categories are NOT always distinct.
67) Explain how an animal with a paralyzing spinal injury can be stimulated to walk, though it cannot walk on its own. Diagram and label the structures involved. (Hint: Keep it simple; for example, you could draw a rectangle and label it "right leg muscle" and another for the left, and don't worry about drawing all neurons involved, just enough to show you understand the basics. You may wish to start with a simple sketch of a muscle reflex then add on to it as necessary.)
68) Diagram and label the knee jerk reflex. What is the physiological function of this reflex? Explain how this reflex may be important during walking, if you did not notice a hole in the sidewalk and stepped into it. What is the role of reciprocal inhibition? How would the reflex be affected if reciprocal inhibition failed? Describe the effects on the reflex of severing each structure involved in the reflex, considering one structure at a time. Describe the effects of damaging the opposite side of the spinal cord, or areas higher or lower on the spinal cord.
69) Draw a diagram of the cerebral motor cortex and descending input to spinal motor neurons. Voluntary suppression of the knee jerk reflex originates in the motor cortex, which can send inhibitory signals to the motor neurons. If the left motor cortex is active, is the left or right knee jerk reflex suppressed or are both suppressed? Explain your answer. If the left side of the spinal cord at the level of leg muscle control is damaged, is it the left or right knee jerk reflex that is suppressed or are both suppressed?
70) While watching Olympic weight lifters through streaming video, Marcus notices that on several occasions an athlete would lift the weight to his chest and then suddenly drop it. Can you offer an explanation for what might be happening?
71) Defecation and bladder control involve spinal reflex pathways that are located in the sacral region of the spinal cord. In both instances, two sphincter muscles, an inner sphincter of smooth muscle and an outer sphincter of skeletal muscle, control the passage of waste out of the body. How would completely cutting the spinal cord at the lumbar level affect an individual's bowel and bladder control?
72) Francisco, an experienced batter, steps up to the plate, looks off into the distance, and plans where to hit the baseball. He then swings the bat, connects with the ball, sends it into the air, and follows through the swing with his arms, hips, and knees, and shifts his weight from one leg to the other. He watches the ball fly away, and takes off for first base. Explain which areas of the central nervous system are working during each phase of the action outlined, and which step is controlled by each part.
B. Continue to integrate this with information from other topics as the action continues: Francisco hears the ump "Infield fly! Batter's out!" He remembers the rules of the game, slows his pace, and leaves the baseline before arri first base.
73) When testing the knee jerk reflex during a routine physical, a nurse notices that the reflex is hyperactive. What could be the explanation for this? If instead the reflex was hypoactive, what may the nurse conclude?
74) Draw two graphs that represent the alpha-gamma coactivation:
1. muscle length as a function of time 2. action potentials of spindle sensory neuron as a function of time
75) Two of your physiology classmates are trying to figure out if cross-country skiing is a voluntary activity or a rhythmic activity. They come to you to determine who is correct. What do you tell them?
Answer Key
Testname: UNTITLED32
1) A
2) E
3) A
4) D
5) B
6) C
7) E
8) E
9) D
10) D
11) A
12) B
13) C
14) E
15) A
16) B
17) B
18) E
19) B
20) C
21) F
22) A
23) D
24) G
25) E
26) B
27) A
28) B
29) C
30) B
31) B
32) alpha motor neurons
33) Gamma
34) muscle tone
35) reciprocal innervation
36) the absence of excitatory
37) central pattern generators
38) Proprioceptors
39) visceral
40) Somatic
41) monosynaptic
42) polysynaptic
43) negative feedback
44) corticospinal tract
45) Feedforward, cessation
46) 1. decision-making and planning
2. initiating the movement
3. executing the movement
47) False. Normal muscles maintain a resting tension known as muscle tone.
48) A
49) E
50) D
51) stretch, sensory, tension, relaxation (Golgi tendon organs are relatively insensitive to muscle stretch.)
52) myotatic unit, monosynaptic stretch reflex, sensory, muscle spindle, somatic
53) No. Relaxation is a passive process that normally follows contraction and occurs in the absence of further activity in the motor neurons. Inhibition involves prevention of muscle stimulation and consequent contraction by activity in interneurons that inhibit motor neurons. While in both cases the motor neuron is not producing signals, the reason is lack of stimulation in one case, inhibition in the other.
54) 1. the spinal cord, which integrates spinal reflexes and contains the central pattern generators
2. the brain stem and cerebellum, which control postural reflexes and hand and eye movements
3. the cerebral cortex and basal ganglia, which are responsible for voluntary movements
55) Any three of the following four answers are correct classifications. Further, the effector or action is sometimes evident b reflex name, e.g., flexor reflex. Answers to specific reflexes will vary, e.g., knee jerk reflex is somatic, spinal, innate, and monosynaptic.
1. by the efferent division of the nervous system that controls the response: somatic reflexes and autonomic reflexes
2. by the CNS location where the reflex is integrated: spinal reflexes and cranial reflexes
3. by whether the reflex is innate or learned: innate reflexes and learned or conditioned reflexes
4. by the number of neurons in the reflex pathway: monosynaptic reflexes and polysynaptic reflexes
56) See Table 13.1 and Figure 13.1 in the chapter.
57) Stretching activates the stretch reflex, which in turn contracts the muscle, thereby preventing overstretching.
58) See Figure 13.1 in the chapter.
59) See Figure 13.2 in the chapter.
60) While reflexes can be exploited by medical personnel as a means to assess neural and muscular function, that is not their "purpose" in the sense of why they occur. Each reflex has a function; for example, the knee jerk reflex helps control movement at the knee joint.
61) Alpha motor neurons control the contraction of skeletal muscle fibers. Gamma motor neurons adjust the stretch sensitivity of the muscle spindle, so that the spindle is active even when the muscle shortens. Coactivation of both sets of fibers causes the tension on the muscle spindles to be maintained as the muscle shortens; thus sensitivity to stretch is maintained.
62) See Table 13.2 in the chapter.
63) See Figure 13.7 in the chapter.
64) Skeletal muscle reflexes have the following components: Sensory receptors known as proprioreceptors–the three types are: muscle spindles, Golgi tendon organs, and joint receptors. Sensory neurons carry input from proprioreceptors to the CNS, the integrating center. Somatic motor neurons carry the output signal from the CNS; alpha motor neurons are somatic motor neurons that innervate skeletal muscle contractile fibers, known as extrafusual muscle fibers.
65) See Figure 13.1 in the chapter. The answer should include each component of the reflex pathway as in Figure 13.1. Monosynaptic reflex has a single synapse between the afferent and efferent neurons; polysynaptic reflexes have two or more synapses.
66) The three categories are reflex, voluntary, and rhythmic. Reflex movements are initiated by sensory input and are integrated primarily in the spinal cord. Voluntary movements are integrated in the cerebral cortex and require no external stimuli. Rhythmic movements are a combination of reflex and voluntary. Voluntary movements improve with practice as do reflexive, voluntary movements can become reflexive once learned, and voluntary movements depend upon input from postural reflexes.
67) If the animal is supported on a moving treadmill, the central pattern generators involved in walking will become active and will produce coordinated contraction and relaxation of limb muscles. Diagram should include a cross section of the spinal cord with an area labeled "central pattern generator," a sensory afferent, and a motor efferent as in any sketch of a reflex.
68) The diagram should resemble Figure 13.5 in the chapter. The function of the reflex is to control movement at the knee joint. If you stepped down farther than you expected, your opposite knee may bend more than it would have, activating the reflex and straightening that leg to prevent you from falling. Reciprocal inhibition allows muscles opposing extension of the leg to be inhibited. If this inhibition failed, leg extension would not occur; instead, the knee would be "locked." Severing the afferent or efferent nerve, the spinal cord at the level of the reflex, or the muscle would all prevent the reflex from occurring. Damage to the opposite side of the spinal cord or areas above or below the cells involved in the reflex should have no effect on the basic reflex. (Note to instructor: In reality, it is not so simple, but the point is to get the students to consider the basic mechanics of the reflex.)
69) The diagram should resemble Figure 13.10 in the chapter. The left motor cortex controls the right spinal motor neurons and therefore the right knee reflex. The left side of the spinal cord controls the reflex on the left side.
70) What Marcus is observing is an example of the stretch reflex in action. As the weight lifter lifts the weight, he is contracting the biceps brachii and brachialis muscles and at the same time stretching the triceps brachii muscle. If the mass is great, the amount of flexion necessary to move the mass could begin to overstretch the triceps that is being relaxed so as not to interfere with flexion. Stimulation of the muscle spindles in the triceps produces a reflex arc that brings about the relaxation of some of the motor units in the muscles involved in flexion, like the biceps. When the tension produced by the flexing muscles decreases to a point where they can no longer work against the resistance of the mass, the weight lifter will drop the weights involuntarily.
71) The person would still exhibit a defecation (bowel) and micturition (bladder) reflex because the spinal reflex is processed at the local sacral level of the spinal cord, which is intact at that level. Efferent impulses from the organs would stimulate specific interneurons in the sacral region that would synapse with the motor neurons controlling the sphincters, thus bringing about emptying when organs began to fill. This is the same situation that exists in a newborn infant who has not yet fully developed the descending tracts necessary for conscious control. The individual with the spinal cord transection would lose voluntary control of the bowel and bladder because these functions rely on impulses carried by motor neurons in the brain that must travel down the cord and synapse with the interneurons and motor neurons that are involved in the reflex. With a lumbar transection, these impulses no longer reach the reflex control center.
72) For part A, see "The Integrated Control of Body Movement" section of the chapter. For part B, students can include information learned in Chapters 9 and 10.
73) A hyperactive knee jerk reflex suggests a lack of descending inhibition. This could indicate injury or disease in the spinal cord above the reflex arc, or in a brain area involved in motor control. A hypoactive reflex could indicate damage to any of the components of the local reflex arc, including the muscle, the spinal nerve, or that level of the spinal cord. Alternatively it is possible the patient is deliberately inhibiting the reflex by descending inhibition. Reflexes can also be adversely affected by metabolic disorders.
74) See Figure 13.4 in the chapter.
75) You explain that they are, to some degree, both correct. While learning to cross country ski, you would set up central pattern generators that would help you repeat predictable orders of movement. Since those movements would be automatic with your brain being responsible for starting and stopping the central pattern generators, it would be a rhythmic activity. However if there is a change in terrain or slope where you are skiing, your brain would have to alter the patterns and adapt to the changing terrain, requiring voluntary motions. Most athletic endeavors would involve a combination of voluntary and rhythmic movements.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) In the 17th century, William Harvey discovered evidence that
A) blood is recirculated instead of consumed.
B) the cardiovascular system transports blood and air.
C) arteries and veins are linked by capillaries.
D) the cardiovascular system is an open system.
E) the liver manufactures blood.
2) Capillaries are
A) microscopic vessels in which blood exchanges material with the interstitial fluid.
B) thick walled vessels that carry blood rich in oxygen.
C) thin walled vessels that carry blood toward the heart.
D) thin walled vessels that carry blood deficient in oxygen.
E) thick walled vessels that carry blood away from the heart.
3) An artery is a vessel that
A) is constricted by skeletal muscle contractions.
B) contains internal valves.
C) transports blood away from the heart.
D) transports blood toward the heart.
E) carries highly oxygenated blood.
4) The purpose of valves in the cardiovascular system is to
A) regulate blood pressure.
B) prevent blood from flowing too quickly.
C) provide the force for circulation.
D) ensure that blood flows in one direction.
E) provide sounds so that heart health can be monitored.
5) Which organ is NOT known to include a portal system for blood?
A) brain
B) heart
C) liver
D) kidney
E) All of these organs have portal systems.
6) Which is the first branch from the aorta after it leaves the left ventrical?
A) pulmonary trunk
B) coronary arteries
C) renal arteries
D) carotid arteries
E) hepatic artery
7) The hepatic portal vein carries blood away from the A) kidneys.
B) pancreas.
C) liver.
D) digestive tract.
E) spleen.
8) The driving force for blood flow is a(n) gradient.
A) pressure B) osmotic C) gravity D) volume
9) Which statement about hydrostatic pressure is FALSE?
A) If a fluid is not moving, the pressure that it exerts is called hydrostatic pressure.
B) Hydrostatic pressure does not include the dynamic component of a moving fluid.
C) Force is not equal in all directions.
D) The lateral component of moving fluid represents the hydrostatic pressure.
E) All of the statements are true.
10) Which change will NOT result in increased blood flow to a tissue?
A) increased blood volume
B) decreased peripheral resistance
C) decreased vessel diameter
D) increased blood pressure
E) relaxation of precapillary sphincters
11) Which increases resistance?
A) decreased length
B) decreased viscosity
C) increased blood vessel radius
D) decreased flow
E) decreased friction
12) As blood vessel length increases,
A) flow decreases only.
B) resistance increases and flow decreases.
C) friction decreases only.
D) resistance increases only.
E) both resistance and flow increase.
13) Which will increase flow in a vessel the most?
A) decrease length by 1 unit
C) increase radius by 1 unit
B) decrease viscosity by 1 unit
D) All have the same effect on flow.
14) When a quantity is expressed as "4 cm/min," this is describing the A) flow rate.
B) volume.
C) velocity of flow.
D) pressure.
E) pressure gradient.
15) The sac around the heart is the
A) pericardium.
B) pleural sac.
C) peritoneum.
D) epicardium.
E) myocardium.
16) The function of the pericardial fluid is to
A) remove waste products from the heart.
B) reduce friction between the heart and the pericardium.
C) provide oxygen to the heart.
D) provide fuel to the heart.
E) store calcium for the heart.
17) At an intercalated disc,
A) the cell membranes of two cardiac muscle fibers are completely separated by a synapse.
B) two cardiac muscle cells are connected by gap junctions.
C) the myofibrils are loosely attached to the membrane of the disc.
D) t-tubules unite the membranes of the adjoining cells.
E) All of the answers are correct.
18) In the heart, valves are located
A) just between the great veins and the atria.
B) between atria and ventricles and between ventricles and arteries.
C) just between the ventricles and the arteries.
D) just between the right and left ventricles.
E) just between the atria and the ventricles.
19) Which valves have chordae tendineae?
A) bicuspid (mitral) and tricuspid valves
B) semilunar valves
C) valves in veins
D) coronary valves
E) aortic and pulmonary valves
20) The term myogenic indicates that the heart muscle is the source of
A) stem cells that repair damaged heart tissue.
B) the contractile force for pumping.
C) a hormone that regulates blood volume.
D) receptors that stimulate blood pressure reflexes.
E) the electrical signal that stimulates heart contraction.
21) The action potential in a cardiac contractile cell causes
A) opening of HCN channels.
B) opening of L-type calcium channels.
C) opening of ryanodine receptor calcium channels.
D) activation of sodium-potassium ATPase.
E) activation of NCX transporters.
22) Stretching a myocardial cell
A) only decreases the force of a contraction.
B) only allows more Ca2+ to enter.
C) allows more Ca2+ to enter and increases the force of a contraction.
D) decreases the force of a contraction and allows more Ca2+ to enter.
E) only increases the force of contraction.
23) The rapid depolarization phase of the action potentials of myocardial contractile cells is due to which ion(s)?
A) K+ only
B) Ca2+ only
C) Na+ only
D) both Ca2+ and K+
E) both Na+ and K+
24) During the plateau phase of the action potentials of myocardial contractile cells, which ion(s) is/are crossing the membrane?
A) Ca2+ only
B) Na+ only
C) K+ only
D) both Ca2+ and K+
E) both Na+ and K+
25) The flattening of the action potentials of myocardial contractile cells, called the plateau phase, is due to a combination of K+ permeability and Ca2+ permeability.
A) decreasing, increasing
B) increasing, increasing C) decreasing, decreasing
D) increasing, decreasing
26) The action potentials of myocardial autorhythmic cells, are due to a combination of increasing Na+ and Ca2+ and decreasing K+ .
A) efflux, efflux B) influx, influx C) efflux, influx D) influx, efflux
27) The end of the plateau phase of cardiac contractile cell action potentials is due to the of Ca2+ channels and of K+ channels.
A) closing, closing
C) closing, opening
B) opening, opening
D) opening, closing
28) A typical action potential of a myocardial contractile cell lasts millisecond(s).
A) 1-5
B) at least 500
C) 50-100
D) less than 1
E) at least 200 28)
29) The importance of the plateau phase of the action potential of myocardial cells is in
A) preventing overstretching of the cells.
B) preventing fibrillation.
C) enhancing the efficiency of oxygen use by the cells.
D) regulating Ca2+ availability to the cells.
E) preventing tetanus.
30) Autorhythmic cells can generate action potentials spontaneously because they have
A) prolonged Ca2+ influx.
B) channels for Na+ and K+ that are always open.
C) unstable membrane potentials.
D) L-type Ca2+ channels.
E) a net influx of Na+
31) If channels are permeable to
A) Ca2+ and K+
B) Na+ and K+
C) K+ only.
D) Ca2+ only.
E) Na+ only.
32) Autorhythmic cells
A) have organized sarcomeres.
B) contribute to the force of contraction.
C) are also called pacemakers because they set the rate of the heartbeat.
D) are the same size as myocardial contractile cells.
E) None of the answers are correct.
33) The depolarization of the pacemaker action potential spreads from cell to cell through
A) chemical synapses.
C) desmosomes.
34) The fibrous skeleton of the heart is important because it
B) tight junctions.
D) gap junctions.
A) helps guide the blood into the proper chambers in sequence.
B) transmits electrical activity from the atria to the ventricles.
C) directs the flow of blood into the arteries.
33)
D) forces electrical activity to be conducted through the atrioventricular node. 34)
35) The AV node is important because it
A) electrically opens the AV valves.
B) slows the transmission of the electrical impulses to the ventricles in order for the atria to finish contracting.
C) directs electrical impulses from the ventricles to the atria.
D) serves as the pacemaker in a normal heart.
E) None of these answers are correct. 35)
36) The medical term for heart attack is
A) heart murmur.
B) myocardial infarction.
C) heart block.
D) fibrillation.
E) heart failure.
37) In the condition known as complete heart block, what happens?
A) The fibrous skeleton of the heart breaks down, interfering with the passage of blood from the atria to the ventricles.
B) Electrical signals from the SA node never reach the ventricles, so the contraction of the atria is not coordinated with the contraction of the ventricles.
C) The mitral valve leaflets calcify and close, preventing blood from being pumped efficiently by the left side of the heart.
D) Coronary arteries are blocked by plaques, preventing blood and oxygen from reaching the myocardial contractile cells.
E) Blood flow through the foramen ovale is blocked.
38) When the heart is in ventricular fibrillation,
A) the myocardial cells are contracting together as they should; fibrillation indicates a normal sinus rhythm of 75 beats per minute.
B) the myocardial cells deplete their oxygen supply because they are contracting too fast, and lactic acid damages the myocardial cells.
C) effective pumping of the ventricles decreases because the myocardial cells contract in a disorganized manner, and the brain cannot get enough oxygen.
D) the myocardial cells may become damaged from contracting too fast.
E) there is no contraction of the myocardium.
39) Electrical shock to the heart is usually used to treat
A) atrial fibrillation.
B) heart murmur.
C) myocardial infarction.
D) heart block.
E) ventricular fibrillation.
40) ECGs
A) measure the mechanical activity of the heart.
B) show the summed electrical activity generated by all cells of the heart.
C) are most useful in diagnosing heart murmurs.
D) provide direct information about the heart function.
E) have two major components: waves and nodes. 40)
41) The P wave of an ECG corresponds to
A) depolarization of the atria.
B) repolarization of the atria.
C) the progressive wave of ventricular depolarization.
D) repolarization of the ventricles.
E) None of the answers are correct.
42) The QRS complex of an ECG represents
A) the progressive wave of ventricular depolarization.
B) depolarization of the atria.
C) repolarization of the atria.
D) repolarization of the ventricles.
E) None of the answers are correct.
43) A heart rate of 125 beats per minute could be correctly termed
A) fibrillation.
B) an arrhythmia.
C) a normal resting heart rate.
D) bradycardia.
E) tachycardia.
44) Ventricular contraction begins
A) just after the T wave.
B) during the first part of the P wave.
C) just after the Q wave.
D) during the latter part of the P wave.
E) None of the answers are correct.
45) Atrial contraction begins
A) during the first part of the P wave.
B) just after the Q wave.
C) just after the T wave.
D) during the latter part of the P wave.
E) None of the answers are correct.
46) In electrocardiography, a lead is a(n)
A) cable that attaches between the ECG machine and the body.
B) pair of electrodes.
C) electrode.
47) Which electrical event happens at the start of a cardiac cycle?
A) Blood is ejected from the atrium.
B) The P wave develops.
C) The SA node fires.
D) Atrial systole occurs.
E) Ventricular systole occurs.
48) In order for blood to enter the heart,
A) the pressure in the atria must be lower than in the veins.
B) the atria must be in diastole but the atrial pressure must be lower than the veins.
C) the atria must be in diastole.
D) the AV valves must be open.
E) All of the answers are correct. 48)
49) Which event results in the first heart sound?
A) The semilunar valves close.
B) The atria contract.
C) The AV valves close.
D) The AV valves open.
E) The semilunar valves open.
50) During the isovolumic phase of ventricular systole,
A) the atrioventricular valves and semilunar valves are closed.
B) the ventricles are filling with blood.
C) blood is ejected into the great vessels.
D) the atria contract.
E) the ventricles are relaxing.
51) During the cardiac cycle,
A) the third heart sound occurs during atrial systole.
B) the P wave of the ECG occurs between the first and second heart sounds.
C) the QRS complex of the ECG comes before the increase in ventricular pressure.
D) the greatest increase in ventricular pressure occurs during the ejection phase.
E) the second heart sound occurs with the QRS complex of the ECG.
52) During ventricular systole,
A) the atria are contracting.
B) the pressure in the ventricles declines.
C) the ventricles are relaxed.
D) the AV valves are closed.
E) blood is entering the ventricles.
53) During ventricular ejection,
A) the QRS complex is just starting.
B) the AV valves are open.
C) blood is forced into veins.
D) the semilunar valves are closed.
E) the ventricles are in systole.
54) The term used to describe the amount of blood in the ventricle available to be pumped out of the heart during the next contraction is
A) heart rate (HR).
B) cardiac output (CO).
C) end-systolic volume (ESV).
D) end-diastolic volume (EDV).
E) stroke volume (SV). 54)
55) The volume of blood ejected from each ventricle during a contraction is called the
A) end-systolic volume.
B) end-diastolic volume.
C) cardiac reserve.
D) cardiac output.
E) stroke volume.
56) The cardiac output is equal to the
A) product of heart rate and stroke volume.
B) difference between the end-diastolic volume and the end-systolic volume.
C) product of heart rate and blood pressure.
D) difference between the stroke volume at rest and the stroke volume during exercise.
E) stroke volume less the end-systolic volume.
57) The term that describes the volume of blood circulated by the heart in one minute is
A) cardiac output (CO).
B) stroke volume (SV).
C) end-systolic volume (ESV).
D) heart rate (HR).
E) end-diastolic volume (EDV).
58) Epinephrine and norepinephrine increase ion flow through channels.
A) If and Ca2+
B) If only
C) Na+ only
D) Ca2+ only
E) K+ only
59) According to the Frank-Starling law of the heart, the cardiac output is directly related to the
A) heart rate.
B) thickness of the myocardium.
C) venous return.
D) size of the ventricle.
E) end-systolic volume.
60) Which will increase the heart rate?
A) both sympathetic stimulation and epinephrine stimulation of the SA node
B) only the application of acetylcholine to stimulation of the SA node
C) both sympathetic stimulation and acetylcholine stimulation of the SA node
D) only sympathetic stimulation of the SA node
E) only epinephrine stimulation of the SA node
61) Stimulation of the beta receptors on heart muscle results in
A) cAMP signaling.
B) decreased rate of contraction.
C) increased sensitivity to acetylcholine.
D) decreased force of cardiac contraction.
E) All of the answers are correct.
62) Drugs known as beta blockers will
A) decrease heart rate.
B) increase cardiac output.
C) increase heart rate.
D) decrease the end-systolic volume.
E) increase stroke volume. 62)
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the following terms to the correct answer:
63) an AV valve that has three flaps
64) a semilunar valve that has the right ventricle on one side
65) also called the mitral valve
66) has three cuplike leaflets and has the aorta on one side
Match the following terms to the correct answer:
67) immediately followed by ventricular contraction
68) atrial contraction
69) ventricular repolarization
70) ventricular depolarization
71) atrial depolarization
Match each term with its definition.
72) the volume of blood pumped out of the heart from one ventricle during one contraction
73) the volume of blood in the ventricle available to be pumped out of the heart during one contraction
74) the volume of blood circulated from one ventricle in one minute
75) the volume of blood left in the ventricle after it contracts
T wave
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
76) The chambers of the heart that pump blood into the arteries are the . 76)
77) The chambers of the heart that receive blood from the veins are the . 77)
78) The primary function of the cardiovascular system is 78)
79) are blood vessels that carry blood away from the heart. 79)
80) are blood vessels that return blood to the heart. 80)
81) The cardiovascular system is made up of , , and . 81)
82) The first branch from the aorta represents the . 82)
83) Name the three portal systems in the body. 83)
84) The circulation carries blood to and from the alveoli of the lungs. 84)
85) The circulation carries blood from the left ventricle to the body and back to the right atrium. 85)
86) The pressure created in the ventricles is called the pressure because 86)
87) The term for decreased blood supply is 87)
88) The carries blood from the of the heart to the lungs. Backflow of blood to the heart is prevented by the Blood from the lungs returns to the heart through 88)
89) The heart is encased in the 89)
90) The upper part of the heart where the major blood vessels enter and exit is the . 90)
91) The lower point of the heart is called the 91)
92) The is a wall that separates the two sides of the heart. 92)
93) The muscle layer of the heart wall is the 93)
94) The heart is encased in a tough membranous sac called the The heart is made up mostly of muscle tissue, called the 94)
95) The opening between each atrium and its ventricle is separated by the , which connects the ventricular side to collagenous tendons, called muscles provide stability for these tendons. 95)
96) Cell junctions in contractile cells are called , which contain of two parts: and 96)
97) The are calcium channels in cardiac contractile cells. Opening them causes 97)
98) Explain why the AV node delays the transmission of action potentials, it slightly allows: 98)
99) The cells responsible for spontaneously depolarizing and establishing electrical conductance to the cardiac contractile cells are the 99)
100) A heart with cells contracting rapidly in a disorganized manner, with no effective pumping action, is said to be in 100)
101) A tracing of the electrical activity of the heart, monitored by electrodes placed on the skin, is called a(n) 101)
102) The period of time from the beginning of one heartbeat to the beginning of the next is termed the 102)
103) Irregular rhythms of cardiac activity are known as . 103)
104) A resting heart rate of less than 60 beats per minute is identified as 104)
105) A resting heart rate above 100 beats per minute is identified as . 105)
106) An increase in blood vessel diameter is known as 106)
107) The contraction phase of the cardiac cycle is termed 107)
108) The period when blood is pushed into the arteries is called ejection. 108)
109) Listening to the heart through the chest wall is called . 109)
110) Narrowing of the opening of a heart valve is referred to as . 110)
111) The is the amount of blood in a ventricle at the end of atrial systole. 111)
112) The is the amount of blood in a ventricle after it has contracted and before it 112) begins to refill.
113) The rule that states "Within physiological limits, the heart pumps all of the blood that returns to it" is known as the . 113)
114) The amount of blood returning to the heart is the 114)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
115) Place these structures in the order that blood returning to the heart from the body would pass throu them.
1. right ventricle
2. left atrium
3. right atrium
4. pulmonary trunk/pulmonary arteries
5. left ventricle
6. pulmonary veins
A) 1, 3, 6, 4, 5, 2
B) 4, 2, 5, 6, 3, 1
C) 2, 5, 6, 4, 3, 1
D) 3, 2, 4, 6, 1, 5
E) 3, 1, 4, 6, 2, 5
116) If blood pressure doubled at the same time that the peripheral resistance doubled, the blood flow through a vessel would be
A) 16 times greater.
B) unchanged.
C) 1/16 as much.
D) doubled.
E) halved.
117) Doubling which would have the greatest effect on peripheral resistance?
A) diameter of a vessel
B) viscosity of the blood
C) length of a vessel
D) turbulence of the blood
E) number of white cells in the blood
118) Which statement about cardiac muscle is FALSE?
A) The energy demand of cardiac muscle cells is high because they have many mitochondria.
B) Cardiac muscle cells must obey the all-or-none law of contraction.
C) Calcium-induced calcium release is when extracellular Ca2+ stimulates release of Ca2+ from the sarcoplasmic reticulum.
D) Intercalated disks contain both desmosomes for firm attachment and gap junctions to allow communication.
E) Cardiac muscle cells use Ca2+ ions released from the sarcoplasmic reticulum.
119) If the membranes of the cardiac muscle cells in the SA node become more permeable to potassium ions,
A) stroke volume will increase.
B) intracellular concentration of calcium ion will increase.
C) heart rate will increase.
D) the membrane will depolarize.
E) heart rate will decrease.
120) As a result of the long refractory period, cardiac muscle prevents
A) tonus.
B) fatigue.
C) recruitment.
D) tetanus.
E) treppe.
121) Ivabrandine selectively blocks If channels in the heart. Which statement would be true in a patient who is taking this drug?
A) This patient is being treated for bradycardia.
B) The drug would slow down this individual's heart rate.
C) This drug would decrease contractility of the patient's heart.
D) The amount of calcium entering the patient's heart cells would increase.
E) This drug would increase the blood pressure of the patient.
122) Put these autorhythmic cells into the correct order for conveying electrical signals through a normal
1. bundle of His
2. internodal pathway
3. Purkinje fibers
4. atrioventricular node
5. sinoatrial nodes
6. left and right bundle branches
A) 5, 2, 4, 1, 6, 3
B) 5, 4, 1, 6, 2, 3
C) 4, 2, 5, 1, 6, 3
D) 3, 6, 1, 4, 2, 5
E) 5, 2, 1, 6, 4, 3
123) The ECG of a person with complete heart block would show
A) an increased PR interval.
B) no visible T wave.
C) more P waves than QRS complexes per minute.
D) an inverted P wave.
E) a smaller QRS complex.
124) If the connection between the AV node and bundle of His becomes blocked,
A) tachycardia will occur.
B) the ventricles will beat more slowly.
C) the stroke volume will increase.
D) the ventricles will beat faster.
E) the ventricular rate of contraction will not be affected.
125) If a myocardial infarction results in the formation of scar tissue along the pathway of the left bundle branch,
A) the ventricle will contract more forcefully.
B) conduction through the left ventricle would remain normal.
C) cardiac arrhythmias may occur.
D) the right ventricle will fail to contract.
E) blood flow to the lungs will decrease.
126) Abnormally slow conduction through the ventricles would change the in an ECG tracing.
A) PR interval
B) QRS complex
C) P wave
D) T wave
E) RT interval
127) If there is a blockage between the AV node and the AV bundle, how will this affect the appearance of the electrocardiogram?
A) The QRS complex will be longer.
B) There will be more QRS complexes than P waves.
C) The P-R segment will be shorter.
D) The T wave will disappear.
E) There will be more P waves than QRS complexes.
128) Put these phases of the cardiac cycle in the correct order.
1. opening of the semilunar valves
2. isovolumic contraction
3. beginning of atrial systole
4. closure of the AV valves
5. completion of ventricular filling
6. beginning of ventricular systole
7. ventricular relaxation
8. ventricular ejection
A) 3, 2, 6, 1, 4, 5, 8, 7
B) 4, 5, 1, 2, 7, 8, 3, 6
C) 3, 5, 6, 4, 2, 1, 8, 7
D) 3, 2, 6, 4, 5, 8, 7, 1
E) 3, 5, 6, 1, 8, 4, 2, 7 128)
129) Left ventricular pressure is higher than pressure in the aorta during
A) ventricular systole only.
B) ventricular diastole only.
C) atrial systole only.
D) atrial systole and ventricular systole.
E) All of the answers are correct. 129)
130) In which situation would end-systolic volume (ESV) be the greatest?
A) when stroke volume is increased
B) when parasympathetic stimulation of the heart is increased
C) when the force of myocardial contraction is increased
D) when the intracellular stores of calcium are increased
E) when sympathetic stimulation of the heart is increased 130)
131) If the EDV is 140 mL, which other values are most likely to occur in a healthy person?
A) The ESV could be 90 mL and the SV could be 50 mL.
B) Diastolic pressure would be equal to EDV.
C) The cardiac output could be 90 mL.
D) The ESV could be 70 mL and the SV could be 90 mL.
E) The ESV could be 50 mL and the SV could be 90 mL.
132) A drug decreases heart rate by hyperpolarizing cardiac pacemaker cells. This drug probably binds to 132)
A) alpha adrenergic receptors.
C) nicotinic receptors.
B) muscarinic receptors.
D) beta receptors.
133) Under which circumstances would the diameter of peripheral blood vessels be the greatest?
A) decreased parasympathetic stimulation
B) increased parasympathetic stimulation
C) decreased sympathetic stimulation
D) increased sympathetic stimulation
E) both increased parasympathetic and increased sympathetic stimulation
134) Acetylcholine slows the heart rate by just
A) increasing the permeability to Ca2+
B) increasing the permeability to K+ .
C) decreasing the permeability to Ca2+ .
D) increasing the permeability to K+ and decreasing the permeability to Ca2+ .
E) increasing ion influx, thus increasing the rate of depolarization.
135) Sympathetic stimulation increases the heart rate by
A) increasing the permeability to K+ and decreasing the permeability to Ca2+ .
B) just increasing the permeability to K+ .
C) increasing ion influx, thus increasing the rate of depolarization.
D) just decreasing the permeability to Ca2+ .
E) just increasing the permeability to Ca2+ .
136) In which situation would the stroke volume be the greatest?
A) when venous return is increased
B) when calcium channel blockers are present
C) when venous return is decreased
D) when the difference between the end-diastolic volume and the end-systolic volume is small
E) when the force of contraction is decreased
137) Manganese ions block the calcium channels in the cardiac muscle membrane. How would the presence of manganese ions in the extracellular fluid affect the contraction of the heart muscle?
A) The heart would beat less forcefully.
B) The contraction phase would be prolonged.
C) The heart rate would increase.
D) The plateau phase of contraction would be longer.
138) Drugs known as calcium channel blockers can be used to
A) increase sympathetic stimulation of the myocardium.
B) decrease the force of cardiac contraction.
C) increase blood pressure.
D) constrict the coronary arteries.
E) increase stroke volume. 138)
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the change with the cardiovascular event described.
139) The blood pressure in a vessel is 10 units at point A and 10 units at point B. Flow between those points is .
140) The blood pressure in a vessel is 20 units at point A and 10 units at point B. One minute later, the pressure is 15 units at point A and five units at point B. Flow between those points is
141) Babatunde develops a medical condition that decreases his blood viscosity. Assuming no other change (for example, no compensatory reflex), what happens to his blood pressure?
142) When a blood vessel dilates, resistance through that vessel is
143) When a blood vessel dilates, blood viscosity is .
144) You suck milk through a 6-inch straw and through a 10-inch straw; the diameters are identical. Resistance is in the 10-inch straw compared to the 6-inch straw.
145) When a blood vessel dilates, velocity of blood is .
146) Blood pressure decreases during sleep. How does this affect velocity?
147) During fasting, some capillary beds in the digestive tract are closed and therefore have no blood flow. Others are open to meet the minimal need of the tract for blood flow. During eating and as long as food is present in the tract, all capillary beds are open to flow. What happens to total cross-sectional area of vessels in the digestive tract?
148) If total cross-sectional area of blood vessels in an organ increases, what happens to velocity of blood through that organ?
149) If total cross-sectional area of vessels in an organ remains the same but blood flow to that organ increases, what happens to velocity of blood?
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
150) In the autorhythmic cells, the channels open when the cell membrane potential is -60 mV. These channels are permeable to and
151) The resting membrane potential is for skeletal muscle and for contractile myocardium. It is for autorhythmic myocardium.
152) The rising phase of the action potential is a result of for skeletal muscle, for contractile myocardium, and for autorhythmic myocardium.
153) The duration of the action potential is in contractile myocardium, in autorhythmic contractile, and in skeletal muscle.
154) Sympathetic stimulation of the pacemaker cells heart rate by ion flow through and channels.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
155) List and explain the three types of substances transported by the blood. What is the source of each type?
156) What are the main parts of a cardiovascular system? What diffusion-related problem is solved by having a cardiovascular system?
157) Explain what a portal system is and give an example. How is a portal system different from the typical arrangement of vessels?
158) Veins are said to carry deoxygenated blood. Does this mean that there is no oxygen in venous blood? Explain your answer. Are there veins that carry highly oxygenated blood? Again, explain your answer. What color is most venous blood compared to most arterial blood?
159) Define blood flow rate and define blood flow velocity. When an expert in the field uses the term blood flow, does that term usually mean rate or velocity?
160) Discuss the connections between adjacent cardiac muscle cells. What features are important? Is there a disadvantage to this arrangement?
161) What are ryanodine receptor Ca2+ release channels (RyR)? Which type of tissue are they present in? Are all RyRs regulated in the same way? Explain your answer.
162) Explain how Ca2+ levels inside myocardial cells are changed.
163) Draw a diagram of the excitation-contraction coupling and relaxation in cardiac muscles.
164) Explain why a heart can keep beating after it has been removed from a living body.
165) Compare and contrast the appearance of cardiac muscle cells and skeletal muscle cells under the microscope. Continue with an explanation of their similarities and differences in the initiation of their excitation-contraction coupling mechanisms. Finally, end your discussion by comparing their metabolic needs.
166) Compare and contrast the action potentials in the skeletal muscle, contractile myocardium, and autorhythmic myocardium.
167) Why is it necessary to direct the electrical signals in the heart through the AV node instead of allowing them to spread directly from the atria to the ventricles?
168) List the four locations of autorhythmic cells that drive the heartbeat. Draw a sketch of the heart and show the location of each type of cell.
169) Name four questions related to heart function that you could answer by examining an ECG and one abnormal condition that may be indicated by each function.
170) Acetylcholine is excitatory at the neuromuscular junction, but inhibitory at the SA node. Explain why this is true.
171) Compare and contrast the effects of cholinergic and adrenergic signaling on the heart. Include a comparison of the various types of receptors they interact with, and their location on the heart.
172) Explain what is meant by the contractility of the heart. How is contractility controlled?
173) Explain what is meant by the terms respiratory pump and skeletal muscle pump. Why are these important to the cardiovascular system?
174) A chronotropic agent is one that affects the heart rate. Compare and contrast this term with an inotropic agent. Give specific examples of each.
175) Explain how Ca2+ levels inside myocardial cells are important to cell function.
176) Diagram at least seven different factors that affect the components of the equation that relates cardiac output to heart rate and stroke volume. Explain each factor involved.
177) Aluta is a premed student with a summer job as an animal research technician. One of her duties is to withdraw blood by syringe from the anterior vena cava of pigs, to be analyzed for various hormones. During her training she noticed that most blood samples were very dark in color, but occasionally a sample was bright red. Propose an explanation.
178) Juaben is pregnant. Over the next 40 weeks, her uterus will enlarge as the placenta develops and the fetus grows, her abdomen will add skin to accommodate distension, her breasts will grow, her blood volume will increase, and many other changes will occur. Using what you have learned about basic cardiovascular physiology, predict how parameters such as blood pressure and cardiac output will change. (Note that the fetus has a separate cardiovascular system, which does not need to be considered.) Explain your answer.
179) Zamzam is pregnant during the year she is taking human physiology. At each check-up, she expects to be told that her blood pressure has increased. Yet into the final weeks of her pregnancy, her blood pressure is unchanged from its pre-pregnancy value. Why did she expect her blood pressure to increase? Propose some explanations for why it did not. (Hint: Sometimes women adopt healthier habits during pregnancy, there are large blood-filled sinuses in the maternal portion of the placenta, and there are many hormonal effects that are unique to pregnancy.)
180) You are making working models of the heart for extra credit. Your first model failed because the cells separated from each other during beating. What structures did you miss, and why did this allow the heart to fall apart? You missed the gap junctions in your second attempt. How would a real heart fail to function normally without gap junctions?
181) Vern, suffering from cardiac arrhythmias, is brought into the emergency room of a hospital. He begins to exhibit tachycardia and as a result loses consciousness. His anxious partner asks you why he has lost consciousness. How would you respond?
182) What is a normal heart rate for healthy adults at rest, and what neural inputs help the body maintain that range? How is heart rate affected when all nervous system input to the heart is blocked, and why is this effect seen?
183) Atropine inhibits parasympathetic activity. Discuss the effects of atropine on the heart and describe common expected side effects.
184) How many liters of blood are distributed between the pulmonary and systemic circuits in a "typical" person? Assume 20% of the blood is in the lungs at any moment. If the cardiac output is 5 L/min, how long will it take a drop of blood to flow from the right ventricle to the left ventricle?
185) Compare the flow rates (Q) of tubes one and two, assuming the following parameters: Tube one: ΔP = 30, r = 3, L = 20. Tube two: ΔP = 60, r = 4, L = 10.
186) Using the appropriate equations, predict the effects in each scenario.
A. Vessels X and Y have the same diameter. X is 5 cm long and Y is 10 cm long. Which has the faster velocity of f the same fluid?
B. A blood vessel has a radius of 4 cm. Vasoconstriction reduces the radius to 1 cm. In order to maintain the same by what factor must pressure increase?
C. The blood vessel in B above dilates from 1 cm to 4 cm. Does the flow rate increase or decrease?
D. A new subdivision is built between your house and the water storage tower. If the water company makes no adjustments, will the water pressure at your house change? If so, in which direction? Why?
187) A person has a total blood volume of 5 L. Of this total, 4 liters is contained in the systemic circulation and 1 L in t pulmonary circulation. If the person has a cardiac output of 5 L/min:
A. how long will it take for a drop of blood leaving the left ventricle to return to the heart?
B. how long will it take a drop of blood to go from the right ventricle to the left ventricle?
188) If the stroke volume of the left ventricle is 65 mL/beat and the stroke volume of the right ventricle is 68 mL/beat, what will happen to the relative distribution of blood in the systemic and pulmonary circulation after 15 beats?
189) Miguel is a 25-year-old jogger with a target heart rate of 125 bpm. His resting pulse is 70 bpm. His blood volum approximately 6.8 liters. At rest, his cardiac output is 6.3 liters/min.
A. What must his stroke volume be?
B. What might his EDV and ESV be?
C. During his workout, his heart rate increases to 125 bpm and his cardiac output to 12,500 mL/min. Do his SV, E and ESV change with exercise?
190) Using the figure below (Fig. 14.19 from your text), calculate the following values:
Answer Key
Testname: UNTITLED33
1) A
2) A
3) C
4) D
5) B
6) B
7) D
8) A
9) C
10) C
11) D
12) B
13) C
14) C 15) A
16) B
17) B
18) B
19) A
20) E
21) B
22) C
23) C
24) D
25) A
26) D
27) C
28) E
29) E
30) C
31) B
32) C
33) D
34) D
35) B
36) B
37) B
38) C
39) E
40) B
41) A
42) A
43) E
44) C
45) D
46) B
47) C
48) B
49) C
50) A
Answer Key
Testname: UNTITLED33
51) C
52) D
53) E
54) D
55) E
56) A
57) A
58) A
59) C
60) A
61) A
62) A
63) C
64) B
65) A
66) D
67) A
68) D
69) B
70) A
71) C
72) C
73) D
74) B
75) A
76) ventricles
77) atria
78) the transport of materials to and from all parts of the body
79) Arteries
80) Veins
81) the heart, blood vessels, blood (Answers can be in any order.)
82) coronary arteries
83) 1. hepatic portal system
2. renal portal system
3. hypothalamic-hypophyseal portal system
84) pulmonary
85) systemic
86) driving, it is the force that drives blood through the blood vessels
87) ischemia
88) pulmonary trunk (or pulmonary artery/ies), right ventricle, pulmonary valve, pulmonary veins
89) pericardium
90) base
91) apex
92) septum
93) myocardium
94) pericardium, cardiac, myocardium
95) atrioventricular valve, chordae tendineae, Papillary
96) intercalated disks, desmosomes, gap junctions
97) ryanodine receptor Ca2+ release channels (RyR), calcium-induced calcium release
98) the atria to complete their contraction before ventricular contraction begins
Answer Key
Testname: UNTITLED33
99) nodal cells
100) fibrillation
101) electrocardiogram, ECG, or EKG
102) cardiac cycle
103) arrhythmias
104) bradycardia
105) tachycardia
106) vasodilation
107) systole
108) ventricular
109) auscultation
110) stenosis
111) end-diastolic volume (EDV)
112) end-systolic volume (ESV)
113) Frank-Starling Law of the Heart
114) venous return
115) E
116) B
117) A
118) B
119) E
120) D
121) B
122) A
123) C
124) B
125) C
126) B
127) E
128) C
129) B
130) B
131) E
132) B
133) C
134) D 135) C
136) A
137) A
138) B
139) B
140) A
141) C
142) C
143) A
144) D
145) C
146) C
147) B
148) A
149) B
150) If (funny), K+ , Na+
151) -70-80 mV, - 90 mV, an unstable pacemaker potential (usually starts at -60 mV)
152) Na+ entry, Na+ entry, Ca2+ entry
153) extended: 200+ msec, variable: generally 150+ msec, short: 1-2 msec
154) increases, increasing, If , calcium
155) Nutrients, water, and gases from the external environment, substances moving from cell to cell, and waste products to be eliminated from the body. Nutrients and water are absorbed from the digestive tract, gases are absorbed from the lungs, cells secrete substances such as hormones to communicate with other cells, and cells produce waste products as a consequence of metabolism.
156) The main parts are the heart (a pump), the blood, and the vessels, which include arteries, capillaries, and veins. The cardiovascular system solves the problem of inefficient diffusion over large distances by providing a force for the blood and a system of vessels leading to capillaries, which are distributed at a high density throughout all the organs. No living cell is more than a short distance from a capillary.
157) A portal system is a special circulation in which a capillary bed connects to another capillary bed before returning to the general circulation. An example is the hepatic portal system, in which capillaries of the digestive tract are connected to capillaries of the liver by way of the hepatic portal vein. Typically blood in a capillary bed flows through the venous system and back to the heart.
158) Venous blood has some oxygen, but usually less that arterial blood, so it is only relatively deoxygenated. Pulmonary veins are an example of veins carrying highly oxygenated blood. Venous blood is usually dark red, arterial blood is usually bright red.
159) Flow rate is the volume of blood passing by a point per unit time. Velocity is how quickly a given amount of blood passes a point per unit time. Flow rate is usually what the expert is discussing.
160) Cardiac muscle cells are joined by structures called intercalated disks. Abutting cells both have desmosomes, to tightly hold the cells together to withstand the physical force of contraction, and gap junctions, which act as tiny tunnels for ions to cross between cells. In this way, action potentials flow across cardiac muscle cells without disruption, as if the cells were one. One disadvantage of gap junctions is that they can be shut down, promoting fibrillation, which occurs when the cardiac muscle cells contract independently. Rather than producing useful pumping, the heart is only quivering as the teamwork of these millions of cells ceases.
161) Ryanodine receptors are calcium channels, present in cardiac and skeletal muscle tissue. In cardiac muscle they are regulated by calcium, resulting in calcium-induced calcium release from the SR. In skeletal muscle, they are regulated by mechanical linkage to voltage-sensing receptors in SR, thus they are indirectly voltage-regulated.
162) Calcium enters the cell through voltage-gated calcium channels in the cell membrane. Calcium ions then open ryanodine receptor channels in the sarcoplasmic reticulum, resulting in calcium-induced calcium release. Calcium ions are transported back into the SR by a calcium ATPase, or removed from the cell by a sodium-calcium antiport protein.
163) See Figure 14.10 in the chapter.
164) Heart tissue is autorhythmic; thus it does not require stimulation by nerves.
165) See Table 14.3 in the chapter.
166) See Table 14.3 in the chapter.
167) If electrical signals from the atria were conducted directly into the ventricles, the ventricles would start contraction at the top. The blood would be squeezed downward and would be trapped in the bottom of the ventricles.
168) The four areas for the autorhythmic cells are SA node, internodal pathway, AV node, and Purkinje Fibers. See Figure 14.15 in the chapter.
169) 1. What is the heart rate? Abnormal values could indicate tachycardia or bradycardia.
2. Is the rhythm of the heartbeat regular or irregular? Abnormal rhythm could indicate fibrillation.
3. Are all normal waves present in recognizable form? Electrical disorders in atria or ventricles could be indicated.
4. Does a QRS complex follow each P wave, and is the PR segment constant in length? Heart block may be indicated.
170) Acetylcholine receptors in heart muscle are muscarinic, whereas they are nicotinic in skeletal muscle. These receptors are linked to different types of ion channels. At the nicotinic receptor, the response is excitatory due to a sodium influx. At the muscarinic receptor, the response is inhibitory due to a potassium efflux.
171) See Figure 14.20 in the chapter.
172) Contractility is the intrinsic ability of a cardiac muscle fiber to contract at any given fiber length. Contractile force increases with ventricular end diastolic volume, which is determined by venous return. Both the endocrine and nervous systems regulate contractility.
173) Both refer to pressure exerted on the blood in veins that assist in venous return. During the pressure changes in the thoracic cavity associated with normal breathing, pressure in the thoracic portion of the inferior vena cava fluctuates, resulting in blood being drawn upward in the vena cava during each inhalation. Contractile activity of normal skeletal muscle momentarily squeezes the veins within and near the muscles, also helping to propel the blood. These and other slight pressure changes are essential because the overall pressure gradient of the venous system is low.
174) Inotropic agents affect contractility. Catecholamines (epinephrine, norepinephrine) and drugs such as digitalis are positive inotropic agents, meaning they increase contractility. Heart rate is increased by epinephrine (a positive chronotropic agent) and decreased by acetylcholine (a negative chronotropic agent); there is also a variety of drugs that affect heart rate.
175) See Figs. 14.10 and 14.22 in the chapter.
176) See Figure 14.23 in the chapter.
177) Aluta misdirected her needle to a nearby artery instead of withdrawing blood from the vena cava. Arterial blood is more oxygenated than venous blood, thus not as dark.
178) (Note to the instructor: These predictions are logical, but not all actually happen.)
The growth of maternal tissues will require addition of blood vessels, thus total vessel length will increase. This would total peripheral resistance. Blood pressure may increase with increasing blood volume, and also to overcome the greate resistance and return the blood to the heart. Stroke volume should increase; cardiac output may increase as a result, or remain the same if heart rate decreases.
179) (Note to instructor: You may want to alter the hint, providing more or less help, depending on your class activities.) Zamzam assumes that her pressure will elevate with the increased blood volume and increased peripheral resistance th accompany the tissue growth she experiences. It is possible that she has adopted healthier diet and exercise habits durin pregnancy, offsetting an increase in pressure. It is also possible that the changing hormonal environment includes regulation of blood pressure so that it remains normal. It is also the case that the placenta forms a low-resistance reservoir for the maternal blood, offsetting the expected increase in total peripheral resistance and blood pressure.
180) Desmosomes were omitted. Without desmosomes, the contractile force of the heart would be large enough to separate the cells from each other. Without the gap junctions, the electrical currents that stimulate contraction would not be propagated from cell to cell, and the heart would fail to beat.
181) During tachycardia, the heart beats at an abnormally fast rate. The faster the heart beats, the less time there is between contractions for it to fill with blood again. As a result, over a period of time the heart fills with less and less blood and thus pumps less blood out. The stroke volume decreases, as does the cardiac output. When the cardiac output decreases to the point where not enough blood reaches the central nervous system, loss of consciousness occurs.
182) A typical adult heart rate is 60-100 beats per minute. This normal resting value results from the constant parasympathetic inhibition of the higher endogenous rate of the SA node. Without neural input, resting heart rate is higher, matching the intrinsic rate of the SA node, 90-100 beats per minute.
183) Parasympathetic stimulation of the heart has an inhibitory effect, slowing the heart rate. This inhibition is constant under normal circumstances, and without it the heart beats at the rate set by the pacemaker cells, which is higher than normal. Thus atropine, by removing the inhibition, increases heart rate. Other organs affected by atropine include any with muscarinic receptors. For example, atropine would inhibit intestinal motility, resulting in constipation. Atropine also inhibits the pupillary reflex, resulting in dilated pupils.
184) There are about 5 liters of blood in a 70 kg man. If 20% of the blood is in the lungs, then 5 × 0.2 = 1 liter of blood in the lungs.
1 L × 1 min/5 L × 60 sec/1 min × 1 min/60 sec = 12 seconds.
185) Q ΔP/(L/r4) Q1 30/(20/34) = 121. Q2 60/(10/44) = 1535.
Flow rate in the second tube is about 12 times higher than that in the first tube.
186) A. Assuming the same driving pressure, the velocity is the same. Length is not a factor (v = Q/A).
B. 256.
Q ΔP/R, so ΔP R. As R 1/r4, ΔP 1/r4
As Q does not change, ΔP1 × r14 = ΔP2 × r24. r14 = 44 = 256.
C. increase
D. Your water pressure would decline, owing its diversion to the new subdivision houses.
187) A. SV = 5 L/min, volume = 4 L, which would be distributed in 4/5 min = 48 seconds.
B. Volume in the pulmonary circuit = 1 L, which would require 1/5 min, or 12 seconds to return to the left atrium from t right ventricle.
188) With each heartbeat, the left side will get "behind" by 3 mL, with this volume contributing to congestion in the pulmonary circuit; after 15 beats, the deficit will total 45 mL of extra fluid in the pulmonary circuit. This could be the beginning of congestion that sets the stage for congestive heart failure.
189) A. 90 mL CO = SV * HR; SV = CO/HR = 6.3 L/min/ 70 bpm.
B. Combination where EDV minus ESV = 90 mL
Average values are ESV = 44-60 mL, EDV = 134-150 mL.
C. Yes, the SV changes to 100 mL; EDV probably increases proportionately, to 149-167 mL. Thus, the ESV would be 49mL. One would assume an increase in venous return would lead to atrial stretching and an increased EDV.
190) A. (1 cycle/800 msec) × (1000 msec/sec) × (60 sec/min)
= 60,000 cycles/800 min
= 75 cycles (or beats)/min
B. Stroke volume = EDV - ESV = 135 mL - 65 mL = 70 mL/beat
C. Cardiac output = HR × SV = 75 beats/min x 70 mL/beat = 5250 mL/min or 5.25 L/min
D. Mean Arterial Pressure = (DP + DP + SP)/3 = (85 + 85 + 120)/3 = 290/3 = 96.7 mm Hg or MAP = DP + 1/3 (SP-DP) = 85 + 1/3 (120-85) = 85 + 1/3 (35) = 85 + 11.7 = 96.7 mm Hg
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Fainting is also known as
A) reactive hyperemia.
B) orthostatic hypotension.
C) eclampsia.
D) infarction.
E) vasovagal syncope.
2) Perfusion is
A) delivery of oxygen to cells.
B) the connection between capillaries and other vessels.
C) the driving force behind blood flow.
D) blood flow through an organ.
E) movement of blood through a shunt.
3) are also known as the pressure reservoir of the cardiovascular system.
A) Arterioles
B) Arteries
C) Capillaries
D) Venules
E) Veins
4) The inner lining of blood vessels is called
A) endostatin.
B) endothelium.
C) endoangium.
D) basal lamina.
E) endocardium.
5) Smooth muscle is present in the walls of
A) veins only.
B) muscular arteries only.
C) arteries only.
D) all vessel types except capillaries and venules.
E) all vessel types. 5)
6) The highly branched contractile cells that regulate capillary permeability are called
A) pericytes.
B) podocytes.
C) epitheliocytes.
D) vascular smooth muscle.
E) endothelial cells.
7) Differences between arterioles and metarterioles include the idea that arterioles
A) have a continuous smooth muscle layer in their walls and allow blood to bypass capillary beds.
B) have an endothelial lining.
C) allow blood to bypass capillary beds.
D) have a continuous smooth muscle layer in their walls.
E) All of the answers are correct.
8) The only blood vessels whose walls permit exchange between the blood and the surrounding interstitial fluids are the
A) capillaries.
B) venules.
C) arterioles.
D) arterioles and capillaries.
E) venules and capillaries.
9) Angiogenesis is
A) being able to detect a pulse in arteries.
B) an examination of the arteries and veins.
C) having blood drawn into a tube for tests.
D) surgical restructuring of the coronary arteries.
E) the growth of new blood vessels.
10) Angiostatin and endostatin may be useful in the treatment of
A) myocardial infarction.
B) hypertension.
C) cancer.
D) hypotension.
E) vasovagal syncope.
11) The values obtained when measuring blood pressure, such as 120/80,
A) exactly match the pressures inside the ventricle during systole and diastole and reflect the pressure in the major arteries during ventricular systole and diastole.
B) exactly match the pressures inside the ventricle during systole and diastole.
C) estimates the pressure in the major arteries during ventricular systole and diastole.
D) are the same on both the pulmonary and systemic circuits.
E) All of the answers are correct.
12) Which of the following is occurring during systole?
A) pulse pressure decreases
B) blood pressure increases and pulse pressure decreases
C) blood pressure increases
D) more stress is placed on arterial walls
E) blood pressure increases and more stress is placed on arterial walls
13) The mean arterial pressure (MAP) is important because
A) it forces the practitioner to do math, thus they must pay attention to the values obtained.
B) it represents the driving pressure for blood flow and it reflects the difference in time that systole lasts compared to diastole.
C) it represents the driving pressure for blood flow.
D) it reflects the difference in time that systole lasts compared to diastole.
E) All of the answers are correct.
14) Blood flow to a tissue will increase if the
A) pH increases.
B) level of carbon dioxide at the tissue increases.
C) level of oxygen at the tissue increases.
D) vessels constrict.
E) All of the answers are correct.
15) Blood pressure is determined by measuring
A) the size of the pulse pressure.
B) the force exerted by blood in a vessel.
C) the degree of turbulence in a closed vessel.
D) the pressure in the left ventricle.
E) All of the answers are correct.
16) The difference between the systolic and diastolic pressures is called the
A) blood pressure.
B) pulse pressure.
C) systemic pressure.
D) circulatory pressure.
E) mean arterial pressure.
17) Which would NOT cause an increase in blood pressure?
A) a decrease in arterial diameter
C) an increase in sympathetic activity
B) an increase in arterial resistance
D) a decrease in cardiac output
18) The vessels that are the main site of variable resistance in the circulatory system, and that contribute more than 60% of the total resistance, are the
A) elastic arteries.
B) venules.
C) arterioles.
D) muscular arteries.
E) veins.
19) If cardiac output increases and resistance in arterioles does NOT change, what happens to arterial blood pressure?
A) decreases B) increases C) is unchanged
20) Increased blood volume blood pressure.
A) decreases B) increases C) has no effect on
19)
21) Which organ is NOT part of the cardiovascular system and plays an important role in regulating blood pressure?
A) kidney B) lung
C) skin D) spleen E) liver
22) The matching of blood flow to the changing metabolic needs of a tissue is due to A) hormonal control. B) local control. C) neural control.
23) Myogenic autoregulation means that
A) increased blood pressure in a vessel triggers relaxation in that vessel.
B) increased blood pressure in a vessel triggers relaxation in that vessel and blood vessel diameter is adjusted by centers in the brain through monitoring blood pressure in areas throughout the body.
C) stretched smooth muscle in a blood vessel constricts reflexively and blood vessel diameter is adjusted by centers in the brain through monitoring blood pressure in areas throughout the body.
D) stretched smooth muscle in a blood vessel constricts reflexively.
E) blood vessel diameter is adjusted by centers in the brain through monitoring blood pressure in areas throughout the body.
24) Each of the following paracrines may cause vasodilation EXCEPT
A) nitric oxide.
B) K+
C) CO2
D) H+ ions from metabolic acids.
E) Ca2+
25) Reactive hyperemia is
A) lack of blood flow due to an allergic reaction.
B) reflex contraction of smooth muscle in response to stress.
C) increased blood flow following a period of reduced blood flow.
D) increased blood pressure after stress.
E) None of the answers are correct.
26) Reactive hyperemia is triggered by
A) stress and the hormones released during stress.
B) reflex contraction of smooth muscle following a period of dilation.
C) toxins or allergens, such as bee venom or pollen.
D) local accumulation of paracrines due to reduced blood flow.
E) None of the answers are correct.
27) The elevated blood pressure that sometimes accompanies pregnancy is known as
A) infarction.
B) reactive hyperemia.
C) vasovagal syncope.
D) orthostatic hypotension.
E) preeclampsia.
28) In order to cause vasodilation of most vascular smooth muscle,
A) acetylcholine combines with muscarinic receptors.
B) norepinephrine combines with β1 receptors.
C) sympathetic stimulation is removed.
D) acetylcholine combines with nicotinic receptors.
E) norepinephrine combines with alpha receptors.
29) Several blood-borne chemicals affect the lumen size of arterioles. Which are NOT paired correctly?
A) epinephrine – vasoconstriction with alpha receptors
B) sumatriptan – vasoconstriction
C) kinins – vasodilation
D) serotonin – vasodilation
E) histamine – vasodilation
30) whereas pass. capillaries are very porous and allow high volumes of fluids to pass through them, capillaries consist of more tightly joined cells that allow selective materials to
A) Transcytotic, continuous
B) Fenestrated, transcytotic
C) Fenestrated, continuous
D) Continuous, fenestrated
E) Transcytotic, fenestrated
31) Sinusoids are modified vessels that replace in some tissues.
A) capillaries B) arteries C) veins
32) Compared to arteries, the velocity of flow of the blood through the capillaries is
A) about the same.
B) at least 10 times faster.
C) much slower.
D) at least twice as fast.
E) impossible to predict without more information.
33) Due to the differences in opposing forces, there is net occurring at the arteriolar end of most capillaries, coupled with net at the venous end.
A) filtration, absorption
33)
B) absorption, filtration
34) Restoring lost fluid from the capillaries back to the circulatory system is one of the major functions of the system.
A) digestive
B) immune
C) urinary
D) thirst-quenching
E) lymphatic 34)
35) Osmotic pressure resulting from presence of plasma proteins in blood is called pressure.
A) oncotic
B) hydrostatic
C) colloid osmotic
D) oncotic and colloid osmotic
E) colloid osmotic and hydrostatic
36) A parasitic condition resulting in extreme enlargement of one or both legs is called A) elephantosis. B) ascites. C) elephantitis. D) elephantiasis.
37) The integrating center for neural control of blood pressure resides in the
A) pons variolli.
B) hypothalamus.
C) cerebellum.
D) cerebrum.
E) medulla oblongata.
38) Stretch-sensitive mechanoreceptors known as are located in some artery walls.
A) nociceptors B) chemoreceptors C) elasticeptors D) baroreceptors
39) Blood pressure and flow to the brain are monitored by receptors located in the wall of the
A) venae cavae.
B) cephalic arteries.
C) carotid artery.
D) cerebral arteries.
E) aorta.
40) When blood pressure is normal, the receptors in arterial walls fire action potentials A) continuously. B) very seldom.
41) When blood pressure receptors sense a loss of blood pressure, they their firing rate. A) decrease B) increase
42) Blood pressure and cardiac output can be altered according to A) emotional responses.
B) blood oxygen levels.
C) body temperature, emotional responses, and blood oxygen levels.
D) body temperature and emotional responses.
E) body temperature.
43) When the baroreceptor reflex is stimulated by a decrease in blood pressure,
A) peripheral resistance decreases.
B) sympathetic activity increases and cardiac output increases.
C) sympathetic activity increases.
D) cardiac output increases.
E) sympathetic activity increases, cardiac output increases, and peripheral resistance decreases. 43)
44) If a person is in bed for several days, the baroreceptor reflex may fail upon standing. Why?
A) The kidneys have decreased the blood volume.
B) Blood pools in the feet and legs and there is decreased blood flow to the brain.
C) Blood pools in the feet and legs.
D) There is decreased blood flow to the brain.
E) All of the statements are correct.
45) Which of these does NOT increase the risk for cardiovascular disease?
A) having diabetes mellitus
B) menopause without estrogen replacement therapy
C) being a female over 30 but under 55
D) having a sister with coronary artery disease
E) being a male over 30 but under 55
46) For a diagnosis of hypertension, a patient must have
A) a systolic pressure above 120 mm Hg.
B) a systolic pressure above 140 mm Hg.
C) a diastolic pressure below 80 mm Hg.
D) a diastolic pressure above 90 mm Hg.
E) a systolic pressure above 140 mm Hg or a diastolic pressure above 90 mm Hg.
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
47) The endothelium of the blood vessels and its adjacent connective tissue make up the 47)
48) Capillaries lack smooth muscle and elastic or fibrous tissue reinforcement. Instead, their walls consist of , supported on an acellular matrix called 48)
49) Cerebral capillaries are surrounded by and glial cells and have tight junctions that create the . 49)
50) Venules are similar to capillaries: they have epithelium and little . They are distinguished from capillaries by . 50)
51) Blood pressure is highest in the and decreases continuously as blood flows through the circulatory system, due to the lost as a result of the resistance to flow offered by the vessels. 51)
52) The rapid pressure increase that occurs when the left ventricle pushes blood into the aorta can be felt as 52)
53) Venous return to the heart is aided by the and the 53)
54) A rupture of a blood vessel in the brain is called and may cause the loss of neurological function commonly called 54)
55) Mean arterial pressure is (indirectly/directly) proportional to and (indirectly/directly) proportional to . 55)
56) is an increase in blood flow that accompanies an increase in metabolic activity. 56)
57) Norepinephrine binding to alpha receptors on vascular smooth muscle causes and epinephrine binding to alpha receptors on vascular smooth muscle causes 57)
58) The osmotic pressure created by the presence of proteins is known as , which is (higher/lower) in the plasma than in the interstitial fluid. 58)
59) The decrease in blood pressure upon standing is known as . 59)
60) The term for chronically elevated blood pressure is . 60)
61) Loss of pericytes around retinal capillaries is a hallmark of the disease . 61)
62) Capillary exchange involving movement between the endothelial cells is called the pathway. 62)
63) Capillary exchange involving movement through the cells is called transport. 63)
64) The turbulent flow of blood causes a noise called a that can be heard through the stethoscope when taking blood pressure. 64)
65) The structures that regulate blood flow into single capillaries within a tissue are 65)
66) The accumulation of fluid in the interstitial space is called 66)
67) Receptors that monitor blood pressure are called 67)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
68) Compensation for decreased blood volume includes increases in
A) sympathetic stimulation to blood vessels, sympathetic stimulation of the heart, and water conservation by the kidneys.
B) sympathetic stimulation to blood vessels.
C) sympathetic stimulation to blood vessels and water conservation by the kidneys.
D) sympathetic stimulation of the heart.
E) water conservation by the kidneys. 68)
69) Fenestrated capillaries are found in
A) the kidney.
B) skeletal muscles.
C) cardiac muscle.
D) skin.
E) the spleen.
69)
70) Regarding the cardiovascular system, the main role(s) of the kidneys is/are to
A) restore lost fluid to the blood and therefore raise blood pressure.
B) restore lost fluid to the blood and therefore raise blood pressure, and minimize fluid loss from the blood and therefore maintain blood pressure.
C) reduce blood volume and therefore reduce blood pressure.
D) minimize fluid loss from the blood and therefore maintain blood pressure, and reduce blood volume and therefore reduce blood pressure.
E) minimize fluid loss from the blood and therefore maintain blood pressure.
71) Which condition would have the greatest effect on peripheral resistance?
A) doubling the diameter of a vessel
B) doubling the viscosity of the blood
C) doubling the number of white cells in the blood
D) doubling the length of a vessel
E) doubling the turbulence of the blood
72) Which would decrease peripheral resistance?
A) plaques in the vessel walls
B) increased levels of epinephrine
C) factors that cause increased hematocrit
D) increased sympathetic stimulation
E) vasodilation
73) If a female has a blood pressure of 120/80, her mean arterial pressure would be
A) 80 mm Hg.
B) 40 mm Hg.
C) 93 mm Hg.
D) 100 mm Hg.
E) 200 mm Hg.
74) The lymphatic system
A) empties the lymph vessels into the veins near the collarbones.
B) has heart-like pumps called lymph nodes.
C) stores blood when circulatory demand is low.
D) can be removed without health consequences.
E) All of the answers are correct.
75) The cardiovascular control center in the brain can directly cause
A) arterioles to dilate or constrict.
B) arterioles to dilate or constrict and the heart rate to increase or decrease.
C) the heart rate to increase or decrease.
D) the contractility of the heart to increase or decrease.
E) All of the answers are correct. 75)
76) Malnutrition can cause edema because
A) there are not enough nutrients for plasma protein synthesis.
B) there are not enough nutrients for plasma protein synthesis and interstitial protein levels are lower than plasma protein levels.
C) interstitial protein levels are lower than plasma protein levels.
D) the resulting anemia increases blood pressure.
E) All of the answers are correct. 76)
77) The continual movement of fluid through the interstitial space functions to
A) help carry toxins and bacteria to cells of the immune system.
B) assist the transport of insoluble substances that cannot enter the capillaries.
C) flush hormones and wastes from the interstitial space.
D) All of the answers are correct.
78) Edema is likely to occur when
A) the blood hydraulic pressure in a capillary is equal to the blood osmotic pressure.
B) hemorrhage occurs.
C) the heart becomes an insufficient pump.
D) blood hydraulic pressure at the capillary decreases.
E) the concentration of protein in the blood increases.
79) Which is greater?
A) blood pressure when sympathetic stimulation to the heart increases
B) blood pressure when parasympathetic stimulation to the heart increases
80) Which is greater?
A) normal heart rate
B) heart rate during circulatory shock
81) Which of the following is/are (a) possible treatment(s) for hypertension?
A) calcium channel blockers and ACE inhibitors
B) ANP blockers
C) ACE inhibitors
D) chloride leak channel blockers
E) calcium channel blockers
82) Which is greater?
A) blood pressure when the peripheral vessels dilate
B) blood pressure when the peripheral vessels constrict
83) Increased levels of carbon dioxide in the blood will result in decreased
A) heart rate.
B) blood flow to the lungs.
C) cardiac output.
D) parasympathetic stimulation of the heart.
E) All of the answers are correct.
84) Tariq suffers from hypertension (high blood pressure). Which drug mechanism might help his problem? A drug that
A) stimulates α1 receptors in cardiac muscle tissue.
B) stimulates cAMP formation in cardiac muscle tissue.
C) blocks muscarinic receptors in cardiac muscle tissue.
D) blocks α2 receptors in cardiac muscle tissue.
E) blocks beta receptors in cardiac muscle tissue.
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
85) Because the suffix "itis" means , swelling of the lower extremities due to blockage of lymph flow is NOT called -itis; rather it is called .
86) Three tissues–, , and –do NOT have traditional capillaries. Instead, they have modified vessels called that are (wider/narrower) than a capillary.
87) refers to the mass movement of fluid between the blood and the interstitial fluid as the result of or pressure gradients. If the direction of bulk flow is into the capillary, the fluid movement is called If the direction of flow is out of the capillary, the fluid movement is known as 87)
88) During the fight-or-flight reaction, is released from the adrenal medulla and binds to receptors, found on the vascular smooth muscle of heart, liver, and skeletal muscle arterioles and results in (increased/decreased) blood flow to these organs; the same neurohormone binds to receptors on other tissues, causing (increased/decreased) blood flow to these organs. 88)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
89) Map the following terms: blood distribution, blood volume, cardiac output, diameter of the arterioles, diameter of the veins, fluid intake, fluid loss, heart rate, mean arterial pressure, passive, regulated at kidneys, resistance to blood flow, and stroke volume.
90) List the factors that influence arteriolar resistance, and give an example of each.
91) Define and describe the mechanism of myogenic autoregulation.
92) Compare and contrast the structure and location of arteries, arterioles, capillaries, and veins. How do these differences contribute to the differences in function of each?
93) Draw a map of the baroreceptor reflex, starting with decrease in blood pressure. Indicate on the map the following: stimulus, receptor, afferent pathway, integrating center, efferent pathway, effector, tissue response, systemic response.
94) What effect does a calcium channel blocker have on the heart, the blood pressure, and cardiac output? Why?
95) Why is there a loss of blood volume when a patient is confined to bed for two or three days? What symptoms commonly follow this confinement?
96) Children who suffer from protein starvation have abdomens filled with fluid. How would a shortage of protein in the diet cause this condition?
97) Describe each of the pathologies listed below. Are the risk factors for each the same? Explain your answer.
A. coronary artery disease
B. atherosclerosis
C. myocardial infarction
D. hypertension
E. congestive heart failure
98) What are some dangers of having coronary artery disease? What are some dangers of having hypertension?
99) Outline the relationship between hypertension and the development of congestive heart failure.
100) List the steps and briefly explain what happens in orthostatic hypotension. What reflex counteracts it?
101) By binding to the Ca2+ channel proteins, drugs known as calcium channel blockers have two main effects. Name them. Why are some cells unaffected by these drugs?
102) While you study blood vessel structure in your dorm room, your roommate prepares to bike to his favorite fishing spot. You watch as he puts on his bike shorts, which look very small in his hands but stretch easily then snap back to fit tightly. His fishing shirt is a nonstretchy cotton shirt that fits loosely, with open mesh panels across the back and armpits for ventilation. Thinking about only the basic structural differences in arteries, veins, and capillaries, which of the types of fabrics resemble which vessels, and why?
103) Baroreceptors have stretch-sensitive ion channels in their cell membrane. Increased pressure on the membrane opens the channels and allows ion flow that initiates action potentials. What kind of ion probably flows through these channels and in which direction?
104) Nicotine stimulates cholinergic receptors of the autonomic nervous system. Based on this information, how would cigarette smoking affect the cardiovascular system?
105) The condition known as shock is characterized by a decreased return of venous blood to the heart. How could an upsetting situation such as the sight of a tragic accident or very bad news produce shock?
106) One of the most common signs of polycystic kidney disease is hypertension in an otherwise healthy person. Why would cysts on the kidney lead to higher blood pressure?
107) Nitroglycerine is a medication taken by people who experience chest pain known as angina. One of the major side effects of the medication is that the patient will notice a severe headache. What causes this side effect?
108) The sympathetic nervous system will cause vasodilation in the arteries of many blood vessels, but vasoconstriction in the brain. Why does this occur?
109) Many drugs used to treat migraine headaches contain caffeine. What mechanism does caffeine have that can help with migraine headaches?
110) Josie is in her last weeks of pregnancy. During a routine check-up, she asks why she is suddenly experiencing swollen feet when she wears knee-high stockings (with a tight elastic band just below the knee). She is confused because an older relative wears support stockings to prevent swollen feet. Provide an explanation for her swelling feet and the difference between support hose and knee-high stockings.
111) Dang loves to soak in hot tubs and whirlpools. One day he decides to raise the temperature in his hot tub as high as it will go. After a few minutes in the very warm water, he feels faint, passes out, and nearly drowns. Luckily he is saved by a bystander. Explain what happened.
112) Millie's grandfather suffers from congestive heart failure. Whenever she visits him, she notices that his ankles and feet appear to be quite swollen. She knows that you are a student of anatomy and physiology, and she asks you why this occurs. What would you tell her?
113) Mahmoud, 53, finally visited his doctor, after 6 months of being winded after climbing the two flights of stairs to his apartment. He kept blaming himself for being "out of shape," and thought he would be OK after his spring yard work started, but he wasn't. The doctor wasn't surprised when Mahmoud's blood pressure was 160/110 mm Hg. The doctor prescribed some beta blockers and more tests, including an ECG and blood tests. Why did the doctor want this additional information? What are some items he would check in the blood tests, and why?
114) Siegfried cuts an artery, and now blood is leaking out of the resulting hole. His blood pressure decreases. Draw a flow chart showing the cardiovascular reflex responses that follow to compensate for the drop in blood pressure.
115) Compare and contrast the types of pressure and flow in systemic and pulmonary circuits , using simple diagrams or tables. Be as complete and specific as possible. You do not need to provide values for the pressures, but you should indicate the relative strength of the different pressures.
116) Describe what a nurse hears through the stethoscope while using a blood pressure cuff, and explain what the sounds represent.
117) Given what you know about blood pressure at various locations in the circulatory system, what pressure is actually determined during a standard blood pressure measurement? Why is the arm the chosen location for determining blood pressure? Is there a more accurate way to determine blood pressure?
118) While a nurse takes a blood pressure measurement on a patient, what determines how much the pressure cuff should be inflated? How would the nurse determine if he inflated the cuff too much? Too little?
119) Calculate the pulse pressure for each example listed.
A. a person with a blood pressure of 120/80 mm Hg
B. a person with a blood pressure of 130/95 mm Hg
120) Calculate the mean arterial pressure (MAP) for each example listed.
A. a person with a blood pressure of 120/80 mm Hg
B. a person with a blood pressure of 130/95 mm Hg
121) Malik's peripheral resistance has increased by 10%. To prevent his mean arterial pressure from changing, what factor must change to compensate, and by how much?
122) Using the appropriate formula, what effect does changing the following vessel diameters have on blood flow?
A. diameter = 8 mm, decreasing to 6 mm
B. diameter = 8 mm, increasing to 12 mm
C. diameter = 10 mm, decreasing to 5 mm
D. diameter = 10 mm, increasing to 20 mm
123) Place these organs in order of descending percentage of blood flow received at rest: bones and other connective, brain, digestive organs and liver, heart, kidneys, lungs, skeletal muscle, skin.
124) Colloid osmotic pressure in plasma is fairly constant in a healthy person. How would protein starvation affect this pressure? How may a very high-protein diet affect this pressure? Suppose a person is suffering from an imbalance that causes an increase in colloid osmotic pressure from the typical 25 mm Hg to 30 mm Hg. Calculate the effect on net fluid flow across the capillary. What negative health consequences could result?
Answer Key
Testname: UNTITLED34
1) E
2) D
3) B
4) B
5) D
6) A
7) D
8) E
9) E
10) C
11) C
12) E
13) C
14) B
15) B
16) B
17) D
18) C
19) B
20) B
21) A
22) B
23) D
24) E
25) C
26) D
27) E
28) C
29) D
30) C
31) A
32) C
33) A
34) E
35) D
36) D
37) E
38) D
39) C
40) A
41) A
42) C
43) B
44) A
45) C
46) E
47) tunica intima or intima, tunica media
48) a flat layer of endothelium, the basal lamina
49) pericytes, blood-brain barrier
50) a thin exchange, connective tissue (Fig. 15.2), their convergent pattern of flow
Answer Key
Testname: UNTITLED34
51) arteries, energy
52) pulse
53) skeletal muscle pump, respiratory pump
54) a cerebral hemorrhage, a stroke
55) directly, cardiac output, directly, resistance of arterioles
56) Active hyperemia
57) vasoconstriction, vasoconstriction
58) colloid osmotic or oncotic pressure, higher
59) orthostatic hypotension
60) hypertension
61) diabetic retinopathy
62) paracellular
63) endothelial
64) Korotkoff sound
65) precapillary sphincters
66) edema
67) baroreceptors
68) A
69) A
70) D
71) A
72) E
73) C
74) A
75) B
76) A
77) D
78) C
79) A
80) B
81) A
82) B
83) D
84) E
85) "inflammation of," elephant, elephantiasis
86) the bone marrow, the liver, the spleen, sinusoids, wider
87) Bulk flow, hydrostatic, osmotic, absorption, filtration
88) epinephrine, β2, increased, α, decreased
89) See Figure 15.8(b) in the chapter.
90) 1. Sympathetic reflexes. Example: temperature regulation.
2. Local control of arteriolar resistance matches tissue blood flow to the metabolic needs of the tissue–Example: paracrin respond to low oxygen, high carbon dioxide.
3. Hormones such as those that regulate salt and water excretion by the kidney.
91) Myogenic autoregulation is the self-regulation by the vascular smooth muscle in response to an increase in blood pressure. The mechanism responsible for the intrinsic response of vascular smooth muscle is stretch that opens mechanically gated Ca2+ channels in the muscle membrane. Calcium entering the smooth muscle cell combines with calmodulin and activates myosin light chain kinase, which in turn increases myosin ATPase activity and crossbridge activity.
92) See Figure 15.2 in the chapter for a summary of structural differences in vessel walls. Arteries contain relatively more smooth muscle, for active regulation of vessel diameter. Large, elastic arteries have more elastic fibers, so that the vessel can stretch and recoil with ventricular contraction and relaxation, thereby minimizing fluctuation in blood pressure. Capillaries are thin and porous, reflecting their role in exchange of substances with the interstitial fluid. Veins contain valves to prevent backflow of blood, which is especially important in leg veins.
93) See Figure 15.14 in the chapter.
94) Calcium channel blockers inhibit the opening of calcium channels and ensuing calcium current. Vascular smooth muscle dilates, and heart rate decreases. Vasodilation will result in a decrease in systemic blood pressure, and the decrease in heart rate will decrease cardiac output.
95) Inactivity causes edema, because of the lack of skeletal muscle pump. The accumulated fluid of edema represents loss from the blood capillaries. This decreased blood volume causes decreased blood pressure, which may give the patient a sense of light-headedness upon standing.
96) Protein is needed by the body for proper growth, maintenance, and reproduction. If someone is malnourished, there aren't sufficient building blocks to make albumin. This results in the inability to maintain a proper colloid osmotic pressure. As a result there will be a loss of fluid from the from the cardiovascular system and it will buildup in the interstitial fluid.
97) A. Coronary blood vessels become blocked by cholesterol or blood clots, causing reduced blood flow.
B. Atherosclerosis is hardening of the arteries, which results from accumulation of cholesterol and other lipids, prolifera vascular smooth muscle, and hardening due to calcification and fibrosis. The bulge that forms protrudes into the vessel reducing blood flow.
C. Myocardial infarction is the death of heart cells as a result of blocked blood flow.
D. Hypertension is high systemic blood pressure that develops as a result of increased peripheral resistance.
E. Congestive heart failure occurs after prolonged hypertension, when the cardiac muscle can no longer generate the ne cardiac output against the high peripheral resistance. As left cardiac output decreases, fluid backs up into the lungs. Oxygenation of the blood decreases, the heart becomes even weaker, leading to more fluid accumulation, and eventually death.
98) This is discussed in the "Cardiovascular Disease" section of the chapter.
99) This is discussed in the "Cardiovascular Disease" section of the chapter.
100) Orthostatic hypotension is the decrease in blood pressure upon moving rapidly from a stable reclining position to standing. While reclining flat, gravity is distributed equally and so is blood. When moving to a standing position, blood initially pools in the lower extremities and cardiac output drops from about 5 L/min to about 3 L/min. Arterial blood pressure then decreases. The baroreceptor reflex should counteract orthostatic hypotension.
101) Binding to calcium channels makes them less likely to open, effectively blocking the normal inward calcium current that would result from neural or endocrine stimulation. This causes vasodilation and a decrease in heart rate. Insensitive tissues have a different subtype of calcium channel.
102) The bike shorts stretch and recoil like elastic arteries, the cotton weave is floppy and nonstretchy like veins, and the mesh is porous like capillaries.
103) Action potentials are created when a cell depolarizes to threshold. Depolarization results from net influx of positive ions or efflux of negative ions. The most likely ion is Na+ , moving into the receptor cell.
104) Since cholinergic receptors are found in all of the ganglia of the autonomic nervous system, you would expect nicotine to stimulate both sympathetic and parasympathetic responses in the cardiovascular target tissues. In response to increased sympathetic stimulation the heart would beat faster and more forcefully. At the same time, however, increased parasympathetic stimulation would decrease the blood flow to the heart muscle. The increased heart rate and force of contraction would contribute to increased blood pressure as would vasoconstriction of peripheral blood vessels as a result of sympathetic stimulation.
105) The upsetting stimuli would be processed by the higher centers of the central nervous system and relayed to the hypothalamus. The hypothalamus could suppress the vasomotor center of the medulla, resulting in fewer sympathetic impulses to peripheral blood vessels. This would cause a decrease in sympathetic tone in the smooth muscle of the blood vessels, resulting in vasodilation. The vasodilation would cause blood to pool in the extremities, decreasing the amount of blood returning to the heart and producing shock.
106) Cysts developing on the kidney will put pressure on the kidneys and decrease the ability of the blood vessels in the kidney to filter out urine, causing an increase in plasma in the blood and higher blood pressure.
107) Nitroglycerine is a vasodilator that is non-specific (the nitric oxide content causes all blood vessels it contacts to dilate). When it is ingested it will cause dilation of the coronary arteries, reliving the chest pain and preventing myocardial infarction, but it will also cause dilation of cerebral blood vessels, causing a headache.
108) Because the brain needs a relatively constant flow of blood, whether the body is at rest or under stress, it will try to maintain a constant level of perfusion to the brain. Since the sympathetic nervous system increases heart rate, blood will flow to the brain faster than it does while at rest, so by constricting the arteries, it will decrease the amount of blood each beat that reaches the brain and thereby keeping a fairly constant amount of blood flowing to the brain.
109) Migraine headaches are caused by dilation of blood vessels in the brain. Caffeine is a drug that mimics the sympathetic nervous system. Since the sympathetic nervous system causes vasoconstriction in the brain, it will counteract the effects of migraine headaches.
110) The elastic band in one of Josie's stocking is so tight that it constantly compresses her veins just in the area under the elastic. This reduces venous return, increasing pressure below that area and causing fluid to exit her blood. Support stockings are medical devices that apply uniform pressure along their entire length, and so produce no constriction. They increase pressure slightly, continuously aiding venous return much like a muscle pump does intermittently.
111) In response to the high temperature of the water, Dang's body shunted more blood to the superficial veins to decrease body temperature. The dilation of the superficial veins caused a shift in blood to the arms and legs and resulted in a decreased venous return. Because of the decreased venous return, the cardiac output decreased and less blood (and less oxygen) was delivered to the brain. This caused Dang to feel light-headed and faint, nearly causing his demise.
112) In heart failure, the heart is not able to produce enough force to circulate the blood properly. The blood tends to pool in the extremities and as more and more fluid accumulates in the capillaries, the blood hydraulic pressure increases. This results in a fluid shift from the blood to the interstitial space. The fluid accumulation exceeds the ability of the lymphatics to drain it and as a result, edema occurs and produces the obvious swelling.
113) Abnormalities on the ECG would reveal evidence of scarring or damage to the heart and the myocardium; blood tests would be checked for electrolyte levels, especially calcium, sodium, and potassium, as well as for changes associated with volume fluctuation. Heart enzymes would not be elevated unless damage was very recent.
114) As blood exits the vasculature, there is a loss in blood volume, which in turn causes the systemic blood pressure to decrease. Baroreceptors (stretch receptors) in the carotid and artery walls are less stretched, and therefore their action potential firing frequency decreases. The baroreceptors project to the cardiovascular control center in the medulla oblongata. In response to decreased baroreceptor input, the cardiovascular control center stimulates sympathetic output and inhibits parasympathetic output. Sympathetic activity causes vasoconstriction and consequent increases in peripheral resistance and blood pressure. Decreased parasympathetic activity causes the SA node firing rate to increase and therefore heart rate increases. Combined with the sympathetic stimulation of the ventricles and consequent increase in contraction force, cardiac output increases as a result, also helping to increase blood pressure.
115) Systemic and pulmonary blood flow is equal to the cardiac output, which is about 720 L/day, or 0.5 L/min. Blood pressure in the pulmonary circulation is 25/8
116) During a normal reading, the first thing the nurse hears is the absence of sound, because there is no blood flowing through the brachial artery; she has successfully compressed the artery with the inflated cuff. As soon as she has released enough pressure to allow blood to flow again, she hears the rumbling sounds of turbulent blood flow through a partially compressed artery. As she continues to release pressure, eventually the blood flows smoothly again as the artery is no longer compressed. The cuff pressure at the initial sound is the systolic blood pressure, and the cuff pressure when the sounds then disappear is the diastolic blood pressure.
117) The pressure in the brachial artery is what is determined, but it is assumed to be very close to the pressure in the aorta, which is the desired information. The arm is chosen for proximity to the heart and convenience; farther from the heart in linear distance, the systolic pressure will be lower and the difference between systolic and diastolic will be less. A more accurate way to determine blood pressure in the aorta would be to place pressure sensors inside the vessel, though this is an invasive and unnecessary procedure given the reliability of the brachial pressure.
118) How much to inflate the cuff is determined from what systolic pressure is expected. Therefore, factors such as age and weight, BP history, and suspected cardiovascular pathology are relevant. The higher the cuff pressure, the greater the chance of causing a patient pain. The nurse would not know for certain he had inflated the cuff too much until he opened the valve to reduce pressure, and determined the systolic blood pressure, at which point he could conclude that he inflated the cuff more than necessary. If he had inflated the cuff insufficiently, he would hear sounds associated with flowing blood as soon as he begins to listen through the stethoscope.
119) Pulse pressure is systolic P minus diastolic P.
A. 40 mm Hg
B. 35 mm Hg
120) MAP = diastolic P + 1/3 (systolic P - diastolic P)
A. MAP = 80 + 1/3 (40) = 93 mm Hg
B. MAP = 95 + 1/3 (35) = 107 mm Hg
121) MAP CO × R
Malik's cardiac output will have to decline by 10%.
122) Flow ΔP/R and R 1/r4
A. Radius changes from 4 to 3, 44 = 256, 34 = 81, 256/81 = 3.16, so flow decreases by a factor of 3.16.
B. Flow increases by a factor of 5.06.
C. Flow decreases by a factor of 16.
D. Flow increases by a factor of 16.
123) Lungs (100%) > liver and digestive (27%) > skeletal muscle (21%) > kidneys (20%) > brain (14%) > bone and other (9%) > skin (5%) > heart (4%).
124) Protein starvation would reduce this pressure whereas excess protein would increase this pressure. Absorption would be affected in this way: πin = πIF - πcap Assuming πIF = 0 mm Hg,
πin = -30 mm Hg, favoring absorption. This is a 20% increase in absorption pressure. This would raise blood volume and blood pressure over normal.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) The total volume of blood in the body of a 70-kg man is approximately liters. A) 25 B) 4 C) 5 D) 2 E) 10
2) Plasma is mostly
A) organic molecules.
B) blood cells.
C) water.
D) ions.
E) proteins.
3) The most prevalent proteins in blood plasma are
A) fibrinogens.
B) albumins.
C) globulins.
D) lipoproteins.
E) transport proteins.
4) Mast cells in tissues are a type of
A) lymphocyte.
B) neutrophil.
C) basophil.
D) eosinophil.
E) monocyte.
5) Monocytes leave the circulation to go to the tissues, where they are called
A) eosinophils.
B) neutrophils.
C) lymphocytes.
D) macrophages.
E) basophils.
6) The cell that is the progenitor of all the types of blood cells is called the A) megakaryocyte.
B) pluripotent hematopoietic stem cell.
C) progenitor.
D) committed progenitor cell.
E) reticulocyte.
7) The percentage of cells in marrow that become white blood cells is about %. A) 10 B) 90 C) 25 D) 75 E) 50
8) Colony-stimulating factors are cytokines made by
A) fibroblasts from bone marrow.
B) white blood cells only.
C) endothelial cells.
D) endothelial cells, fibroblasts from bone marrow, and white blood cells.
E) endothelial cells and fibroblasts from bone marrow.
9) Which statement(s) about colony-stimulating factors (CSFs) is/are FALSE?
A) CSFs regulate leukopoiesis and CSFs are made by epithelial cells.
B) CSFs are required to induce both cell division and cell maturation.
C) CSFs are made by epithelial cells.
D) CSFs regulate leukopoiesis.
10) are a group of diseases characterized by the abnormal growth and development of white blood cells, and are diseases where patients have too few white blood cells.
A) Leukemias, anemias
B) Anemias, leukemias
C) Neutropenias, leukemias
D) Leukemias, neutropenias
E) Neutropenias, anemias
11) regulates the growth and maturation of megakaryocytes.
A) Erythropoietin
B) Thrombopoietin
C) Interleukin
D) Colony-stimulating factor
E) None of the answers are correct.
12) Red blood cell production is regulated by the hormone
A) thymosin.
B) cobalamin.
C) angiotensin I.
D) erythropoietin.
E) M-CSF.
13) Thrombopoietin is produced in the
A) liver only.
B) liver and kidney.
C) spleen only.
D) bone marrow only.
E) kidney only.
14) In normal adults, red blood cells are formed in
A) yellow bone marrow.
B) the liver.
C) kidneys.
D) the spleen.
E) red bone marrow.
15) The primary organ where erythropoietin is produced is the
A) bone marrow.
B) kidney.
C) spleen.
D) liver.
E) endothelial cells throughout the body.
16) A unique aspect of hematopoiesis is that
A) neutrophils direct all development from the lymph nodes.
B) white blood cell production always results in the same proportion of leukocytes.
C) white blood cell development varies with the specific needs of the body.
D) lymphocytes never die.
17) The stimulus for the release of erythropoietin is
A) hypoxia only.
B) hypoxia and low oxygen levels in the tissues.
C) low oxygen levels in the tissues only.
D) hypoxia, low oxygen levels in the tissues, and low blood pressure.
E) low blood pressure only.
18) Diseases that involve the presence of too many white blood cells have been identified as well as diseases that involve too few white blood cells.
A) True B) False
19) The average life span of a red blood cell is A) 6 months. B) 1 week. C) 1 month. D) 1 year. E) 4 months.
20) The function of red blood cells is to
A) carry oxygen from the lungs to the body's cells.
B) carry nutrients from the digestive system to the body's cells.
C) defend the body against infectious organisms.
D) remove carbon dioxide from the lungs.
E) remove nitrogenous wastes from active tissues.
21) A hemoglobin molecule is composed of
A) just three protein chains.
B) four heme groups but no protein.
C) four protein chains and four heme groups.
D) just four protein chains and nothing else.
E) just two protein chains.
22) The porphyrin ring of heme contains an atom of
A) magnesium.
B) calcium.
C) sodium.
D) copper.
E) iron.
23) The majority of the protein inside a red blood cell is
A) fibrinogen.
B) hemoglobin.
C) immunoglobulin.
D) porphyrin.
E) albumin.
24) The function of hemoglobin is to
A) protect the body against infectious agents.
B) aid in the process of blood clotting.
C) carry oxygen.
D) carry nutrients from the intestine to the body's cells.
E) All of the answers are correct.
25) A hematocrit is used to indicate
A) only coagulation time.
B) only the ratio of red blood cells to the total blood volume.
C) the ratio of red blood cells to the total blood volume and the packed cell volume.
D) only the packed cell volume.
E) All of the answers are correct.
26) A normal adult hematocrit would be approximately %.
A) 45 B) 100 C) 66
10
27) Under normal circumstances, aged and damaged erythrocytes are broken down by the
A) spleen.
B) kidneys.
C) thymus gland.
D) yellow bone marrow.
E) digestive tract.
28) The percentage of whole blood occupied by red blood cells is the
A) differential cell count.
B) specific gravity.
C) pH.
D) viscosity.
E) hematocrit.
29) Red blood cell production increases when
A) protein levels in the blood increase.
B) oxygen levels in the tissues decrease.
C) oxygen levels in the tissues increase.
D) carbon dioxide levels in the tissues decrease.
E) carbon dioxide levels in the tissues increase.
30) The process of red blood cell production is called
A) erythropoiesis.
B) erythropenia.
C) hematopenia.
D) erythrocytosis.
E) hemocytosis.
75
31) Each red blood cell is shaped as a biconcave disk. This allows it to
A) change its shape to squeeze through narrow openings and shrink or swell slightly in response to osmotic conditions.
B) change its shape to squeeze through narrow openings, shrink or swell slightly in response to osmotic conditions, and synthesize new proteins and membrane components readily.
C) synthesize new proteins and membrane components readily.
D) shrink or swell slightly in response to osmotic conditions.
E) change its shape to squeeze through narrow openings.
32) Excess iron in the body is
A) stored in bones.
B) found in white blood cells.
C) stored in the liver.
D) stored in fatty tissues.
E) All of the answers are correct.
33) The carrier protein that transports absorbed iron through the blood is
A) thrombopoietin.
B) erythropoietin.
C) transferrin.
D) hemoglobin.
E) intrinsic factor.
34) Which is/are (a) vasoconstrictor(s)?
A) adenosine diphosphate
B) serotonin
C) serotonin and thromboxane A2
D) platelet-activating factor
E) thromboxane A2
35) Which are the two anticoagulants produced by the body?
A) antithrombin III and plasmin
B) antithrombin III and heparin
C) tissue plasminogen activator and plasmin
D) protacyclin and heparin
E) heparin and plasmin
36) Platelets function in
A) forming temporary patches in injured areas.
B) transporting chemicals important for clotting.
C) contraction after clot formation.
D) initiating the clotting process.
E) All of the answers are correct.
37) Platelets are
A) large cells with a prominent, indented nucleus.
B) large cells that lack a nucleus.
C) small cells with a many-shaped nucleus.
D) fragments of large cells.
E) small cells that lack a nucleus.
38) The extrinsic pathway of coagulation is activated by the
A) activation of a proenzyme exposed to collagen.
B) conversion of prothrombin to thrombin.
C) sticking of platelets to damaged tissue.
D) release of heparin from the liver.
E) release of tissue factor by a damaged endothelium.
39) The intrinsic pathway of coagulation is activated by the
A) sticking of platelets to damaged tissue.
B) release of tissue factor by a damaged endothelium.
C) activation due to exposed to collagen.
D) release of heparin from the liver.
E) conversion of prothrombin to thrombin.
40) The common pathway of coagulation begins with the
A) sticking of platelets to damaged tissue.
B) activation of a proenzyme exposed to collagen.
C) release of tissue factor by a damaged endothelium.
D) activation of a clotting factor that converts fibrinogen to fibrin.
E) activating of a clotting factor that converts prothrombin to thrombin.
41) The process of fibrinolysis
A) draws torn edges of damaged tissue closer together.
B) forms emboli.
C) activates fibrinogen.
D) dissolves clots.
E) forms thrombi.
42) Tissue factor is released after initiation in the
A) extrinsic pathway.
B) intrinsic pathway.
C) fibrinolytic pathway.
D) retraction pathway.
E) common pathway.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the following plasma proteins with the correct function
43) contribute(s) significantly to osmotic pressure of plasma
44) help(s) defend the body against microorganisms
45) essential to the process of blood clotting
46) bind(s) with iron in the blood
47) a category that includes clotting factors and enzymes
Match the following terms with the correct descriptions.
48) These cells contain hemoglobin and iron.
49) These are fragments of a megakaryocyte.
50) Phagocytic, these cells make up the majority of WBCs.
51) A type of granulocyte, these have red granules.
52) Often called immunocytes, these cells direct the activities of the immune system.
Match the name of the pathological condition with its description.
53) general term for when the blood cannot transport enough oxygen to the tissues
54) a genetic condition where red blood cells have deficient cytoskeletons
55) genetic condition resulting in crescent moon-shaped red blood cells
56) a stem cell dysfunction that produces too many blood cells
57) Caused by a dietary deficiency, this condition results in red blood cells that are small and pale.
B) iron-deficiency anemia C) polycythemia vera
D) sickle cell disease
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
58) Plasma consists of blood minus and .
59) Active bone marrow is red because of the presence of whereas inactive marrow is because of an abundance of adipocytes. 59)
60) Blood is approximately % plasma by volume. 60)
61) Hormones Cytokines called are involved in regulation of white blood cell populations. 61)
62) In healthy adults, blood cell production occurs only in the . 62)
63) The term used for a cytokine that is released by one white blood cell that acts on another is . 63)
64) The growth and maturation of megakaryocytes is regulated by the glycoprotein . 64)
65) The hormone that regulates the production of red blood cells is . 65)
66) The carrier protein that transports absorbed iron through the blood is . 66)
67) The condition where the skin and the whites of the eyes appear slightly yellow is called 67)
68) The condition where the skin and the whites of the eyes appear slightly yellow is due to high blood levels of the substance 68)
69) Plasminogen is activated by an enzyme called 69)
70) In hemostasis, vasoconstriction is rapidly followed by mechanical blockage of the hole by a . 70)
71) The break down of fibrin by plasmin is known as 71)
72) The two main components of plasma are and . Name two other components found in plasma. 72)
73) Red blood cells in the circulation live for about The short life span is due to increasing of the older red blood cells, which may rupture as they squeeze through capillaries, 73)
74) , , and are called granulocytes because they contain inclusions that give them a granular appearance. 74)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
75) Name two cytokines involved in hematopoiesis. What is the name of the cytokine that plays an important role in the immune system?
76) What is a differential white cell count and when is it used?
77) What are the three major steps of hemostasis?
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
78) The usual treatment for neonatal jaundice is exposing the infant to certain wavelengths of light. The infant wears only a diaper and undergoes the light treatment continuously for several days, even at night. Why can the infant's treatment then be discontinued?
A) because the transition between fetal hemoglobin to adult is complete
B) because light treatment stimulates liver growth
C) because the light generates additional RBCs
D) because the digestive tract is then large enough to secrete bile
E) All of the answers are correct. 78)
79) How would a decrease in the concentration of iron in the blood affect the process of hemostasis?
A) Coagulation would proceed more rapidly.
B) Coagulation would proceed more slowly.
C) Platelet plugs would fail to form.
D) Retraction would occur prematurely.
E) There would be no effect.
80) People with hemophilia A fail to produce a functional factor VIII; as a result,
A) they do not have a functional common pathway.
B) they do not have a functional extrinsic pathway.
C) they do not have a functional intrinsic pathway.
D) their clotting times are shorter than normal.
E) All answers are correct. 80)
81) Kareem suffers from a severe liver disease. Which symptoms would you expect to see as a result of this condition?
A) accumulation of fluid in the tissue spaces of the extremities
B) increased levels of bilirubin in the blood
C) decreased clotting ability
D) decreased blood osmotic pressure
E) All answers are correct. 81)
82) Meghan thinks she has an abscessed tooth (a bacterial infection). If she does, which type of white blood cell would you expect to see in elevated numbers in a differential count?
A) neutrophils
B) eosinophils
C) lymphocytes
D) monocytes
E) basophils 82)
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match each leukocyte to its normal percentage in a differential cell count.
83) basophils
84) eosinophils
85) monocytes
86) neutrophils
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
87) Name the two mechanisms and the factors involved that limit the extent of blood clotting within a vessel.
88) Name the five types of white blood cells. Which type develops into macrophages? Which white blood cells are known as phagocytes and why?
89) A person who goes from sea level to a city that is 5000 feet above sea level will show an increased hematocrit within 2 to 3 days. Draw the reflex pathway that links the hypoxia of high altitude to increased red blood cell production.
90) Define, compare, and contrast "clot busters" and anticoagulants; describe how each works.
91) Summarize the steps of hemostasis.
92) Summarize the steps of the coagulation cascade.
93) Blood clotting is thought to be an example of a positive feedback situation. Explain why this is so, and demonstrate the appropriate steps or areas of hemostasis as part of your explanation.
94) Give two morphological characteristics of erythrocytes. Why is each advantageous to the cell?
95) Make a map using the following terms: bile, bilirubin, ferritin, heme, hemoglobin, intestine, iron in diet, kidney, plasma, spleen, transferrin. You may also add additional terms.
96) Name the process of red blood cell production, the hormone that controls it, the source of that hormone, and the stimulus for its production. Why was the hormone so difficult to isolate and identify?
97) List any five nutrients important for blood cell synthesis and briefly explain the role of each.
98) What is the difference between hemostasis and homeostasis, or are they the same?
99) Define anemia, and explain how it is the same or different from hypoxia. Give examples of three different types of anemia and a brief synopsis of each kind. Is sickle cell disease a true anemia? Explain your answer. When sickle cell disease is fatal, what is the cause of death?
100) A dead human body has been discovered in the woods near your home. You are an expert hematologist, and the body is still warm. This adult corpse has no gender cues (no sexual organs, and skeletal features that are in between those expected for males or females). How can you help the detectives in determining the gender of this person, using hematology lab equipment?
101) What is jaundice? What substance is present in abnormal levels? What can cause jaundice to occur? What difference may inhibit a doctor's ability to diagnose jaundice between people of European compared to African ancestry?
102) How would the process of red blood cell production be affected by constricting the arteries that supply blood to the kidney? Explain your answer. Name three other situations that would similarly affect the process of red blood cell production.
103) In the disease mononucleosis ("mono"), the spleen enlarges because of increased numbers of cells, phagocytic as well as others. Common symptoms of this disease include pale complexion, a tired feeling, and a lack of energy sometimes to the point of not being able to get out of bed. What might cause these symptoms?
104) Erythropoietin (EPO) was first isolated from the urine of anemic patients who had high circulating levels of the hormone. Despite the presence of the hormone that stimulates red cell production, these patients were unable to produce adequate amounts of hemoglobin or red cells. Give some possible reasons that the patients' own EPO was unable to correct their anemia.
105) Mike has classical hemophilia, a clotting disorder, but his case is considered "mild." His levels of factor VIII are 28% of normal. He is usually OK going about the activities of normal daily living. He plays slow pitch softball and enjoys swimming and horseback riding, and is a very active individual who believes "why walk when you can run?" He has noticed that once he has one injury, he will have "bleeds" more readily, and has to restrict his own activities to give himself time to heal. Why would he have to "slow down" longer than a person without hemophilia?
106) Mike has classical hemophilia, a clotting disorder, but his case is considered "mild." Contrary to popular belief, Mike doesn't usually have problematic bleeding episodes related to cutting himself; a more severe problem for him would be brought on by a sprained ankle or by having a full body impact, like falling off a horse and landing hard on the ground, injuries considered "closed." With what you have learned about blood coagulation, can you explain how this could be so? Assuming Mike is lacking factor VIII, which pathways does he depend on?
107) Cancer chemotherapy is designed to destroy cancer cells, but adversely affects healthy tissues as well; thus, the oncologist has the difficult task of killing the cancer without killing the patient. What side effects are expected from destruction of blood cells?
108) An individual who becomes dehydrated will have an increased hematocrit. Explain how dehydration leads to an elevated hematocrit although blood cell production is normal.
109) Explain how anticoagulant drugs can be useful to heart attack or stroke patients.
110) Which nutrients are required for red blood cell synthesis and why? What is blood doping? How is it detected? How is blood doping different from simply good nutrition?
111) How does altitude affect blood composition and why? How would athletes' performance be affected if they live, train, and compete at different altitudes? Explain your answer, using different scenarios. Is such training a type of doping? Explain.
112) Below are results of a blood analysis for a patient undergoing chemotherapy. The left two sets of bars, labeled "M "Max," represent the target values for each cell type. The other sets of bars show the results of blood counts done corresponding days after chemotherapy was administered. Please answer the following questions.
A. According to the graph, which type of formed elements reached normal values first?
B. Which type came closest to its maximum value?
C. On Day 10, which of the following sets of symptoms/characteristics would the patient most likely exhibit?
1. pale and easily fatigued
2. likely to bruise easily or bleed excessively
3. be at high risk for infections
Explain your choice.
113) Sonja is 28 years old and weighs 132 lb (2.2 lb = 1 kg). Calculate the following values for her, assuming she is an average healthy adult.
A. What is her approximate blood volume?
B. What is her approximate plasma volume?
C. Assuming a normal hematocrit, what is her volume of cellular elements?
D. What is her typical RBC count?
E. WBC?
F. Differential count?
G. Platelets?
H. What hemoglobin level would you expect to find?
114) A study was done in 1998 by Dr. Benjamin Levine to explore the role of altitude training in athletic performance. First he trained athletes at low altitude, then measured their finish times in a 5 kilometer run. Then the athletes were placed into one of the following groups: I, living and training at high altitude; II, living at high altitude and training at low; or III, living and training at low altitude. The athletes were then retested in another low-altitude 5 K race. In this study, what are the control and experimental data? What are the dependent and independent variables? The results are expressed as average change in speed of each group. I: -3.4 sec., II: +13.4 sec., III: -26.7 sec. Graph and interpret the results. Did the results surprise you? Why or why not? Propose some explanations for the lower performance by the live high-train high group. Why wasn't there a live low-train high group?
Answer Key
Testname: UNTITLED35
1) C
2) C
3) B
4) C
5) D
6) B
7) D
8) D
9) C
10) D
11) B
12) D
13) B
14) E 15) B
16) C
17) B
18) A
19) E
20) A
21) C
22) E
23) B
24) C
25) C
26) A
27) A
28) E
29) B
30) A
31) A
32) C
33) C
34) C
35) B
36) E
37) D
38) E
39) C
40) E
41) D
42) A
43) A
44) B
45) C
46) A
47) B
48) B
49) A
50) C
Testname: UNTITLED35
51) E
52) D
53) E
54) A
55) D
56) C
57) B
58) cells, platelets
59) hemoglobin, yellow
60) 55
61) colony-stimulating factors
62) red bone marrow
63) interleukin
64) thrombopoietin (TPO)
65) erythropoietin
66) transferrin
67) jaundice
68) bilirubin
69) tissue plasminogen activator
70) platelet plug
71) fibrinolysis
72) water, proteins
Other components found in plasma include: dissolved organic molecules, ions, trace elements and vitamins, and dissol oxygen and carbon dioxide.
73) 120 days, fragility
74) Basophils, eosinophils, neutrophils, cytoplasmic
75) See Table 16.1 in the chapter. Interleukins play an important role in the immune system.
76) Differential white cell count estimates the relative numbers of the five types of white blood cells. It is used by clinicians for diagnosis. See discussion under "Colony-Stimulating Factors Regulate Leukopoiesis."
77) 1. vasoconstriction
2. temporary blockage of a break by a platelet plug
3. blood coagulation, or formation of a clot that seals the hole until tissues are repaired
78) A
79) E
80) A
81) E
82) A
83) D
84) A
85) B
86) C
87) 1. inhibition of platelet adhesion: prostacyclin
2. inhibition of coagulation cascade: plasminogen and plasmin and anticoagulants
88) 1. lymphocytes
2. monocytes
3. neutrophils
4. eosinophils
5. basophils; monocytes develop into macrophages; neutrophils, monocytes, and macrophages are collectively known a phagocytes because they engulf and ingest foreign particles such as bacteria.
89) Low atmospheric at high altitude → low arterial oxygen in the plasma→ sensed by kidney → erythropoietin synthesized and released → acts on bone marrow to increase production of red blood cells.
90) Clot busters are enzymes that destroy clots that have already formed, while anticoagulants prevent clots from forming in the first place.
91) See Figure 16.8 in the chapter.
92) See Figure 16.10 in the chapter.
93) In the blood clotting process, each step triggers a new step(s), by activating enzymes or putting components together that were previously separated. Some of the products formed "feed back" to enhance earlier reactions, sustaining the cascade until some components are completely consumed. See Figure 16.9 in the chapter.
94) Lack of a nucleus and the biconcave shape contribute to flexibility for moving through narrow capillaries and disk shape which aides in responding to osmotic changes.
95) Maps will vary. See Figure 16.6c in the chapter.
96) Production of red blood cells is called erythropoeisis. It is stimulated by the kidney-produced hormone erythropoietin, in response to hypoxia. It was difficult to isolate and identify because it is made on demand rather than stored, and thus is not present all the time.
97) Table 16.2 in the chapter lists B12, folic acid, and iron and a brief explanation of each one's role. The student savvy in metabolism will also note the need for the amino acids for the protein chain synthesis, and energy nutrients in order to supply adequate ATP for these synthetic reactions to occur, as well as the vitamins necessary for the TCA cycle and other aspects of metabolism, including niacin, riboflavin, and pantothenic acid.
98) Hemostasis is the process that minimizes blood loss from the body. Homeostasis is the process that maintains normal physiology. Hemostasis is a type of homeostasis.
99) Anemia is a condition in which the blood's hemoglobin content is too low. Hypoxemia means low oxygen in blood, which could be due to an impaired respiratory system and can therefore occur independent of anemia. Because oxygen binds to hemoglobin, individuals with anemia cannot transport as much oxygen to the tissues, resulting in fatigue and weakness. This may be especially noticeable with exercise Some major causes of anemia are summarized in Table 16.3 in the chapter. Sickle cell disease is considered an anemia because the amount of normal hemoglobin is low. Death is related to hypoxia-caused tissue damage.
100) Assuming you can collect and centrifuge the blood soon, prior to clotting and decay, a hematocrit may provide clues. While a differential white cell count is independent of gender, hematocrit, hemoglobin concentration, and red cell count are all slightly lower in females. See Figure 16.3 in this chapter.
101) Jaundice simply means yellowing of skin and the whites of the eyes. It results when bilirubin levels in the blood become elevated (hyperbilirubinemia); superficial blood vessels allow the imparting of yellow color to skin and eyes. During erythrocyte breakdown, the heme is converted in the spleen and liver to a colored pigment called bilirubin. Bilirubin is carried by plasma albumin to the liver where it is metabolized and incorporated into bile (see Fig. 16.8 in the chapter). Bile is secreted into the digestive tract, and the bilirubin metabolites leave the body in the feces. Small amounts of other bilirubin metabolites are filtered from the blood into the kidneys, where they contribute to the yellow color of the urine. The accumulation of bilirubin can occur from multiple causes. Newborns, whose fetal hemoglobin is degraded and replaced with adult hemoglobin, are particularly susceptible to jaundice, so doctors closely monitor bilirubin levels in the first weeks of life. Another common cause of jaundice is liver disease, where the liver is unable to process and/or excrete bilirubin. People with darker skin don't display the yellowing to the same extent as lighter-skinned people, but the yellowing in the eyes should be about the same.
102) Red blood cell production would be increased. Constricting arteries would reduce blood flow; thus, the kidney would experience hypoxia. The kidney produces the hormone erythropoietin, which stimulates red blood cell production, in response to hypoxia. Increased red blood cell production would also result from anemia, extended presence at high altitude, and following hemorrhage.
103) A major function of the spleen is to destroy old, defective, and worn-out red blood cells. As the spleen increases in size, so does its capacity to eliminate red blood cells, and this produces anemia. The decreased number of red blood cells decreases the blood's ability to deliver oxygen to the tissues and thus metabolism is slowed down. This would account for the tired feeling and lack of energy. Because there are fewer red blood cells than normal, the blood circulating through the skin is not as red, and so the person has a pale skin coloration.
104) Some other factor that is essential for red blood cell synthesis must be lacking. These would include iron for hemoglobin production, folic acid, and vitamin B12
105) A level of 28% suggests that Mike's body synthesizes factor VIII much more slowly than normal. Thus, once he is injured, he depletes his limited supply more quickly and takes longer to replenish it.
106) Only the intrinsic pathway requires factor VIII for activation; the extrinsic pathway and the common pathway are unaffected by the lack of factor VIII. The extrinsic pathway is activated by tissue damage, so even in a person with hemophilia, these may function at close to normal levels.
107) Side effects include anemia from loss of red blood cells, impaired immune function from loss of white blood cells, and impaired coagulation from loss of megakaryocytes.
108) Hematocrit = packed red blood cell volume/total blood volume. A dehydrated person will have a lower plasma volume, but red blood cell volume will remain constant. This results in an elevated hematocrit and the condition known as relative polycythemia.
109) The ischemia that accompanies a "heart attack" or stroke may be prevented by the administration of anticoagulants, which prevent clot formation.
110) Amino acids for globin synthesis, iron for heme synthesis, folic acid and vitamin B12 for DNA synthesis are among the nutrients required. Blood doping is using a treatment to increase the oxygen-carrying capacity of blood, such as receiving a transfusion of red blood cells or administering hormones that stimulate red blood cell production. Hemoglobin concentration in the blood is elevated above normal in dopers, as is hematocrit. Reticulocyte count indicates an accelerated rate of red blood cell production, which would be expected with use of erythropoietin or similar drugs. These drugs/hormones can be detected in the blood. Good nutrition should ensure that hematocrit and hemoglobin are at their maximum, but nutrition is not sufficient to elevate these parameters above normal.
111) Spending several days at higher than normal altitude will stimulate erythropoiesis, due to the lower oxygen concentration in the air, which when breathed would result in hypoxemia. Athletes would be less competitive if they competed at a higher altitude than that in which they lived or trained, and more competitive if they lived and trained at a higher altitude than that in which they competed, at least in theory. While students may not know this, experimental results support the best regimen for maximizing performance at a low-altitude competition to be living at high altitude but training at low altitude. Neither living and training high nor living and training low achieved the same results. High-altitude training is necessary, however, for high-altitude competition. This is a matter of opinion, but most people would probably argue that these training regimens are natural, and therefore not a type of doping.
112) A. platelets
B. RBCs
C. 3, because the WBC count is the most below minimum values, and it is the WBCs that fight infection.
113) A. 132 lbs = 60 kg. Blood volume is approximately 7% of body weight:
60 kg × 0.07 = 4.2 kg = 4.2 L.
B. If her hematocrit were 40%, then her plasma volume = 60% of her blood volume = 0.6 × 4.2 = 2.5 L. Normal hematocrits may range from 37% to 47% in females.
C. With a hematocrit of 40%, her packed cell volume would be 1.6 L.
D. Values are found in Figure 16.3: RBC count = 3.9 to 5.6 × 106
E. WBC = 4,000 - 11,000.
F. Ranges of normal are presented in Figure 16.3.
G. Platelets = 200,000 - 500,000.
H. Hemoglobin = 12 to 16 g/dL blood.
114) The control data are the running times of the athletes after baseline training at low altitude. The experimental data are the running times of the athletes after the additional training at various altitudes. The independent variable is altitude; the dependent variable is running time. A bar graph showing the baseline and postaltitude training results as a pair of bars for each group would be appropriate. The best training regimen was living high and training low, and the worst was living low and training low. Many would probably predict the best performance by the group that both lived and trained high, because they were constantly in a relatively hypoxic environment, which may have produced the greatest increase in hematocrit. Training at high altitude clearly did not allow for the best performance, possibly because the lower oxygen environment limited the ability to train at maximum potential. Living low and training high would likely show the worst performance, because even sedentary living at high altitudes produces an increase in hematocrit; only training at high altitude would be insufficient to produce an altitude-related increase.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Which is NOT considered to be a primary function of the respiratory system?
A) protection against pathogens
B) vocalization
C) regulation of pH balance
D) regulation of water balance
E) gas exchange
2) Ventilation is also known as
A) expiration.
B) breathing.
C) blowing.
D) air conduction.
E) inspiration.
3) The upper respiratory tract includes all EXCEPT which of the following?
A) mouth B) nasal cavity C) lungs D) larynx
4) The lower respiratory tract includes
A) all of the bronchial branches and the lungs.
B) all of the bronchial branches, the lungs, and the trachea.
C) all of the bronchial branches.
D) only the lungs.
E) only the trachea.
5) Pulmonary ventilation refers to the
A) movement of dissolved gases from the blood to the interstitial space.
B) movement of dissolved gases from the interstitial space to the cells.
C) movement of dissolved gases from the alveoli to the blood.
D) movement of air into and out of the lungs.
E) utilization of oxygen.
6) Alveolar ventilation refers to the
A) movement of air into and out of the alveoli.
B) movement of dissolved gases from the alveoli to the blood.
C) movement of air into and out of the lungs.
D) movement of dissolved gases from the blood to the alveoli.
E) utilization of oxygen by alveolar cells to support metabolism.
7) The sites of gas exchange within the lungs are
A) bronchioles.
B) alveolar ducts.
C) alveoli.
D) terminal sacs.
E) pleural spaces.
8) Place the following structures of the respiratory tree in the order in which air passes through them.
1. secondary bronchi
2. bronchioles
3. primary bronchi
4. alveoli
5. terminal bronchioles
A) 4, 1, 2, 3, 5 B) 3, 1, 2, 5, 4 C) 1, 3, 2, 5, 4
9) The airway between the larynx and the primary bronchi is the
A) trachea.
B) laryngeal duct.
C) alveolar duct.
D) bronchiole.
E) pharynx.
10) The lungs are surrounded by membranes.
A) pericardial
B) pleural
C) pulmonary
D) costal
E) thoracic
11) The lungs are located in the cavity.
A) pleural
B) thoracic
C) costal
D) pulmonary
E) pericardial
12) Pressure and volume of gas in a container are related to temperature and number of gas molecules. This is known as law.
A) Ohm's
B) Dalton's
C) the ideal gas
D) Boyle's
E) Henry's
13) Type II alveolar cells
A) allow rapid diffusion of gases through their thin membranes, secrete a chemical known as surfactant, and are phagocytic.
B) are phagocytic.
C) secrete a chemical known as surfactant.
D) allow rapid diffusion of gases through their thin membranes.
E) None of the statements are true. 13)
14) Type I alveolar cells
A) are phagocytic.
B) allow rapid diffusion of gases through their thin membranes.
C) allow rapid diffusion of gases through their thin membranes, secrete a chemical known as surfactant, and are phagocytic.
D) secrete a chemical known as surfactant.
E) None of the statements are true.
15) Which feature of the alveoli allows for the ease of diffusion of gases?
A) Elastin fibers allow the alveoli to stretch thin enough for diffusion to occur.
B) Type II alveolar cells secrete surfactant.
C) They are made of a single layer of epithelium.
D) They are made of a single layer of simple squamous epithelium and elastin fibers allow the alveoli to stretch thin enough for diffusion to occur.
16) Surfactant
A) is not found in healthy lung tissue.
B) protects the surface of the lungs.
C) phagocytizes small particulate matter.
D) helps prevent the alveoli from collapsing.
E) replaces mucus in the alveoli.
17) The common passageway shared by the respiratory and digestive systems is the
A) pharynx.
B) esophagus.
C) vestibule.
D) glottis.
E) larynx.
18) When the diaphragm and external intercostal muscles contract,
A) the volume of the thorax increases.
B) the volume of the thorax decreases.
C) expiration occurs.
D) the lungs collapse.
E) the volume of the lungs decreases.
19) Dalton's law states that
A) the volume of gas that will dissolve in a solvent is proportional to the solubility of the gas and the gas pressure.
B) in a mixture of gases like air, the total pressure is the sum of the individual partial pressures of the gases in the mixture.
C) gas volume and temperature are directly proportional.
D) gas volume and pressure are inversely proportional.
E) None of the answers are correct.
20) Air moves into the lungs because
A) the thorax is muscular.
B) contraction of the diaphragm decreases the volume of the pleural cavity.
C) the volume of the lungs decreases with inspiration.
D) the gas pressure in the lungs is less than outside pressure.
E) All of the answers are correct.
21) Air moves out of the lungs because
A) the volume of the lungs decreases with expiration.
B) contraction of the diaphragm increases the volume of the pleural cavity.
C) the thorax is muscular.
D) the gas pressure in the lungs is less than outside pressure.
E) All of the answers are correct.
22) In quiet breathing,
A) inspiration and expiration are both passive processes.
B) inspiration involves muscular contractions and expiration is passive.
C) inspiration and expiration involve muscular contractions.
D) inspiration is passive and expiration involves muscular contractions.
E) None of the answers are correct.
23) Boyle's law states that gas volume is
A) inversely proportional to temperature.
B) directly proportional to temperature.
C) directly proportional to pressure.
D) inversely proportional to pressure.
E) None of the answers are correct.
24) Air entering the body is filtered, warmed, and humidified by the A) lungs.
B) lower respiratory tract.
C) alveoli.
D) upper respiratory tract.
E) parts of the upper and lower respiratory tract.
25) A typical value for intrapleural pressure is mm Hg.
0
+3
+20
26) According to the law of LaPlace, when comparing two alveoli lined with fluid, pressure in the one with the diameter will be greater.
A) larger B) smaller
27) When alveolar pressure is equal to atmospheric pressure, air flows into the lungs.
A) True B) False
28) Active expiration is produced by contraction of
A) internal intercostals only.
B) diaphragm only.
C) abdominal muscles and internal intercostals.
D) abdominal muscles only.
E) external intercostals only.
29) When the diaphragm, external intercostal and scalene muscles contract,
A) the volume of the lungs decreases.
B) expiration occurs.
C) intrapleural pressure decreases.
D) intrapulmonary pressure increases.
E) All of the answers are correct.
30) If a student inhales as deeply as possible and then blows the air out until he cannot exhale any more, the amount of air that he expelled is his
A) minimal volume.
B) vital capacity.
C) expiratory reserve volume.
D) inspiratory reserve volume.
E) tidal volume.
31) Total cross-sectional area with each division of the airways.
A) decreases B) increases C) does not change
32) Blood vessels cover approximately % of the alveolar surface.
A) < 10 B) 50 C) > 90 D) 80-90 E) 10-20
33) In the lungs, the
A) blood flow rate is lower and the blood pressure is lower, than the blood flow rate and the blood pressure in other tissues.
B) blood flow rate and the blood pressure are the same as in other tissues.
C) blood flow rate is lower and the blood pressure is higher, than the blood flow rate and the blood pressure in other tissues.
D) blood flow rate is higher and the blood pressure is higher, than the blood flow rate and the blood pressure in other tissues.
E) blood flow rate is higher and the blood pressure is lower, than the blood flow rate and the blood pressure in other tissues.
34) The distance between the alveolar air space and capillary endothelium is , allowing gases to diffuse between them.
A) long, rapidly
B) short, slowly
C) long, slowly
D) short, rapidly
E) None of the answers are correct–distance does not affect diffusion rate.
35) Flow of air
A) is directly proportional to a pressure gradient, and flow decreases as the resistance of the system increases.
B) is directly proportional to a pressure gradient, and flow increases as the resistance of the system increases.
C) is directly proportional to the resistance, and flow increases as the resistance of the system increases.
D) is directly proportional to the resistance, and flow decreases as the pressure of the system increases.
E) None of the answers are correct.
31)
32)
33)
34)
35)
36) An increase in PCO2 would cause the bronchioles to
A) constrict and the systemic arterioles to dilate.
B) constrict and the systemic arterioles to constrict.
C) dilate and the systemic arterioles to dilate.
D) dilate and the systemic arterioles to constrict.
E) None of the answers are correct.
37) Chronic inhalation of fine particles that reach the alveoli leads to lung disease.
A) congestive
B) compliant
C) fibrotic
D) obstructive
E) restrictive
38) Poiseuille's law is summarized this way.
A) P1V1 = P2V2 B) PV = nRT C) P = 2T/r D) R Lη/r4
39) Histamine's primary role in the respiratory system is as a
A) bronchoconstrictor.
B) surfactant.
C) vasoconstrictor.
D) vasodilator.
E) bronchodilator.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the lung volume with its description.
40) the additional air inhaled after a normal inspiration
41) the minimum amount of air always present in the respiratory system, after blowing out all you can
42) the extra amount actively (forcibly) exhaled after a normal exhalation
43) the amount of air taken in during a single normal inspiration
Match the lung capacity with its description.
44) the amount of air remaining in the lungs after a normal breath
functional residual capacity
45) the sum of all the lung volumes
46) the amount of air inhaled during an active (forced) inspiration
47) the total amount of air that can be exchanged at will
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
48) The beating of the cilia of the respiratory passages in the direction of the pharynx forms a 48)
49) When the inspiratory muscles relax, the rib cage returns to its original position as a result of 49)
50) The ease with which the lungs stretch in response to changes in pressure is termed 50)
51) The ability of a lung to recoil, or recover from stretch, is called . 51)
52) In the disease , many symptoms are due to destruction of elastic fibers in the lung. 52)
53) Some have a congenital alpha-1 antitrypsin deficiency. If the job of alpha-1 antitrypsin is to inhibit trypsin and elastase, what condition are people with this genetic deficiency likely to develop? 53)
54) The substance produced by the lungs to reduce surface tension is called . 54)
55) The cells of the lung that produce the substance that lowers surface tension are 55)
56) Because of their smooth muscle component, the structures of the lower respiratory system that can most alter airway resistance are the 56)
57) A powerful bronchoconstrictor released by mast cells is 57)
58) Ongoing diseases in which air flow during expiration is diminished are known as 58)
59) An increase in the rate and volume of breathing is known as 59)
60) The volume of air moved in a single respiration is called the . 60)
61) The volume of air that can be forcefully expelled from the lungs following a normal exhalation is called the 61)
62) The volume of air that can be forcefully inhaled after a normal inspiration is called the 62)
63) The volume of air that remains in the lungs after a maximal expiration is called the 63)
64) A typical residual volume (in milliliters) for a healthy, 70 kg male is about 64)
65) The consist of light, spongy tissue whose volume is occupied mostly by air-filled spaces. 65)
66) The opposing layers of pleural membrane are held together by a thin film of 66)
67) The larynx contains the , connective tissue bands that tighten and vibrate to create sound when air moves past them. 67)
68) The primary function of the alveoli is 68)
69) The pressure contributed by a single gas in a mixture of gases is known as . 69)
70) A is an instrument that measures the volume of air moved with each breath. 70)
71) Air flows into lungs because of created by 71)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
72) List the muscles of inspiration and expiration.
73) Define lung capacity, and give a specific example. (Note: There is a specific physiological definition; don't just define "capacity" in general terms.)
74) List and describe the lung volumes.
75) Explain how the upper airways and bronchi condition the air, and why this conditioning is important.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
76) During normal expiration,
A) the abdominal muscles become involved.
B) elastic recoil of stretched muscles helps return the thorax to its resting volume, the internal intercostal muscles are required, and the abdominal muscles become involved.
C) elastic recoil of stretched muscles helps return the thorax to its resting volume and the internal intercostal muscles are required.
D) the internal intercostal muscles are required.
E) elastic recoil of stretched muscles helps return the thorax to its resting volume.
76)
77) Damage to the type II cells of the lungs would contribute to
A) alveolar collapse.
B) decreased surface tension in the water lining the alveoli.
C) alveolar rupture.
D) an increased rate of gas exchange.
E) a thickening of the respiratory membrane.
78) Harry suffers from cystic fibrosis and frequently has periods where he can hardly breathe. The problem is the result of
A) laryngospasms that occur in response to a toxic substance produced by the epithelial cells.
B) inflammation of the bronchi.
C) constriction of the trachea.
D) thick secretions that exceed the ability of the mucus elevator to transport them.
E) collapse of one or both lungs.
79) Breathing that involves active inspiratory and expiratory movements is called because it ensures that a person can increase overall volume.
A) hyperpnea.
B) costal breathing.
C) eupnea.
D) diaphragmatic breathing.
E) shallow breathing.
80) The respiratory rate times the tidal volume corrected for dead space is the
A) respiratory minute volume.
B) pulmonary ventilation rate.
C) alveolar ventilation rate.
D) vital capacity.
E) external respiration rate.
81) Increasing the alveolar ventilation rate will
A) decrease the rate of carbon dioxide diffusion from the blood to the alveoli.
B) decrease the rate of oxygen diffusion from the alveoli to the blood.
C) increase the partial pressure of oxygen in the alveoli.
D) increase the partial pressure of carbon dioxide in the alveoli.
E) have no effect on either the partial pressure or diffusion rate of gases. 81)
82) In the lungs, an example of the body's reserve capacity is that
A) pulmonary blood flow is completely under the control of the autonomic nervous system, dilating arteries and arterioles to adjust blood flow.
B) capillary beds in the lungs are reversibly collapsible, allowing blood to be shunted to additional areas during exercise.
C) some areas of the lung can be closed off during rest and opened again when needed during exercise.
D) All of the statements are true.
E) None of the statements are true. 82)
83) Joe is playing in an intramural football game when he is tackled so hard that he breaks a rib. He can actually feel a piece of the rib sticking through the skin, and he is having a difficult time breathing. Joe probably is suffering from
A) an obstruction in the bronchi.
B) a collapsed trachea.
C) a pneumothorax.
D) decreased surfactant production.
E) a bruised diaphragm.
84) In a condition known as pleurisy, there is excess fluid in the pleural space. How would you expect this to affect the process of pulmonary ventilation?
A) More air would be forced out during expiration.
B) Tidal volume would increase.
C) Breathing would be labored and difficult.
D) Ventilation would require less energy.
E) It would be easier to expand the lungs on inspiration.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the type of breathing with its description.
85) cessation of breathing
86) increased respiratory rate and/or volume without increased metabolism
87) increased respiratory rate and/or volume due to increased metabolism
88) rapid breathing
89) difficulty breathing
B) hyperventilation
E) hyperpnea
Match the change in gas composition with the response (disregard weak responses).
90) Arteries: systemic constrict, pulmonary dilate.
91) Bronchioles and systemic arteries dilate.
92) Arteries: systemic dilate, pulmonary constrict.
93) Bronchioles and systemic arteries constrict.
A) PCO2 decreases.
B) PO2 increases.
C) PCO2 increases.
D) PO2 decreases.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
94) Which single muscle contributes most to normal, resting inspiration?
95) Determine the difference between cellular and external respiration.
96) Describe the pleura and explain its role in respiration.
97) Distinguish between intrapulmonary and intrapleural pressure.
98) What is surfactant? Why is it important?
99) Premature babies frequently need to be put on a respirator to help them breathe. Why does this become a necessary treatment for many premature babies?
100) What is Dalton's law? Why is it important?
101) Air flow in the respiratory system and blood flow in the cardiovascular system have many similarities–name them. How are they different?
102) What are the functions of pleural fluid?
103) Summarize the four gas laws.
104) During the winter, Ali sleeps in a dorm room that lacks a humidifier for the heated air. In the mornings he notices that his nose is "stuffy," similar to when he has a cold, but after showering and drinking some water, the stuffiness disappears until the next morning. What might be the cause of Brad's nasal condition?
105) A newborn infant is found dead, abandoned by the road. Among the many questions that the police would like to have answers to is whether the infant was born dead or alive. After an autopsy, the medical examiner tells them that the infant was dead at birth. How could the medical examiner determine this?
106) Ralph is taking SCUBA diving classes and is confused as to why he should not hold his breath under water while ascending–his instructor told him he must exhale continuously. What would you tell him?
107) Tenzin is not able to produce surfactant. In order to inhale a normal tidal volume, does her intrapleural pressure have to be higher or lower than for a healthy individual? Explain.
108) A package insert for a medication states that "this medicine is a beta receptor stimulant used to treat symptoms of asthma, emphysema and other breathing conditions. Possible side effects include fast heart rate, nervousness, tremors or nausea." Why would these symptoms be expected?
109) You were the top student in your physiology class last semester. For this reason, your professor has asked that y prepare some class sessions for her physiology class this semester. Specifically, she would like you to discuss the similarities and differences between the cardiovascular and respiratory systems, in terms of pressure gradients a flow.
A. Explain how you will describe the role of the following structures: the pump and the tubes.
B. Explain how you will describe the importance of an open vs. closed system and the relevant differences betwe liquids and gases.
C. What is fundamentally different about the respiratory pump compared to the cardiac pump, and why does th difference exist?
110) How would a spirometer tracing be different in a person with a collapsed lung? Why? What must occur to restore the respiratory function to normal?
111) With what you have learned about pulmonary ventilation, how would you design an artificial respirator to keep patients with paralyzed respiratory muscles alive? How does artificial respiration by a machine compare to mouth-to-mouth respiration?
112) Ariana "gets the wind knocked out of her" during a skiing accident in which she attempted a jump and landed hard on her feet before tumbling over. She is conscious but breathing is labored, and she complains of pain and shortness of breath. The first aid-trained ski patrol person that comes to her aid determines that Ariana has no broken bones, nor is CNS injury likely. He places tiny tubes at her nostrils that blow air (with higher than normal percentage of oxygen) into her nose then places her on the snowmobile, and takes her to the first aid tent. Why is Ariana's breathing labored? How does the high-oxygen air help her condition?
113) Nami is breathing 14 times per minute, with a tidal volume of 520 mL and a dead space of 152 mL. Lyle is breathing 15 times per minute, with a tidal volume of 400 mL and a dead space of 175 mL. Which patient has better alveolar ventilation?
114) Weiru is taking 14 breaths per minute. Her vital capacity is 3000 mL, her total lung capacity is 4000 mL, and her volume is 450 mL per breath. Calculate the following:
A. Weiru's total pulmonary ventilation (minute volume)
B. Weiru's alveolar ventilation rate
115) There is a mixture of gases in dry air, with an atmospheric pressure of 760 mm Hg. Calculate the partial pressure gas for the examples below:
A. 20.7% oxygen, 78.2% nitrogen, 0.4% carbon dioxide
B. 45% oxygen, 41% nitrogen, 3% carbon dioxide, 11% hydrogen
C. 79% oxygen, 15% nitrogen, 5% carbon dioxide, 1% argon
116) Draw and label a spirogram showing respiratory activity in a resting person. Draw and label a spirogram in this same person during exercise.
117) Draw three graphs showing how the following change during normal inspiration and expiration:
A. alveolar pressure
B. intrapleural pressure
C. volume of air moved
118) A. Omar is snorkeling (surface swimming with a tube in his mouth to maintain breathing while his face is in the The snorkel tube is 40 cm in length and 1.2 cm in radius. How does this affect Omar's breathing? Calculate the in relative resistance contributed by the snorkel tube.
B. What is dead space and how does that affect snorkeling? Explain your answer, assuming the snorkel tube is a cylinder and cylinder volume is pr2L. How does the snorkel tube affect alveolar ventilation (assume a ventilatio of 12 breaths/min, tidal volume of 500 mL, and normal dead space volume of 150 mL)? If normal alveolar ventila 4200 mL/min, how must Omar breathe during snorkeling compared to normal?
C. Omar loves snorkeling, but wishes he could go a little deeper. He decides to create a longer snorkel tube to try achieve this desire. He isn't sure how radius figures in, so he makes two tubes of 60 cm length, one with a 1.2 cm radius and the other with a 2 cm radius. What are the relative resistances of these two new tubes? Do you think he will be able to snorkel well with either of these tubes? Explain.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
119) Alexandra is breathing in a gas composition that contains an increased concentration of CO2. How would the pulmonary arteries react to this and why?
A) Dilate: increase blood flow through the alveoli
B) Dilate: decrease blood flow through the alveoli
C) Constrict: increase blood flow through the alveoli
D) Constrict: decrease blood flow through the alveoli
Answer Key
Testname: UNTITLED36
1) D
2) B
3) C
4) A
5) D
6) A
7) C
8) B
9) A
10) B
11) B
12) C
13) C
14) B 15) C
16) D
17) A
18) A
19) B
20) D
21) A
22) B
23) D
24) E
25) E
26) B
27) B
28) C
29) C
30) B
31) B
32) D
33) E
34) D
35) A
36) C
37) C
38) D
39) A
40) A
41) B
42) C
43) D
44) A
45) A
46) C
47) B
48) mucociliary escalator
49) elastic recoil
50) compliance
51) elastance
52) emphysema
53) emphysema
54) surfactant
55) type II alveolar cells
56) bronchioles
57) histamine
58) obstructive lung diseases
59) hyperventilation
60) tidal volume
61) expiratory reserve volume
62) inspiratory reserve volume
63) residual volume
64) 1200 mL
65) lungs
66) pleural fluid
67) vocal cords
68) the exchange of gases between themselves and the blood
69) partial pressure
70) spirometer
71) pressure gradients, a pump
72) Inspiration: diaphragm, external intercostals, scalenes, and sternocleidomastoids.
Expiration: internal intercostals, abdominal wall muscles.
73) A lung capacity is the sum of two or more lung volumes. The lung capacities are total lung capacity, vital capacity, functional residual capacity, and inspiratory capacity.
74) residual volume (quantity of air that cannot be expelled), expiratory reserve volume (quantity of air that is expelled only with forced expiration), tidal volume (quantity of air that is inhaled and exhaled under a specific condition, usually normal resting breathing), inspiratory reserve volume (quantity of air that can be inhaled with a forceful inspiration)
75) Air is warmed to body temperature to protect alveoli and avoid disrupting body temperature, air is humidified so that the exchange epithelium will not dehydrate, and foreign material is filtered out so it will not reach the alveoli.
76) E
77) A
78) D
79) A
80) C
81) C
82) B
83) C
84) C
85) A
86) B
87) E
88) D
89) C
90) B
91) C
92) D
93) A
94) The diaphragm muscle provides most of the force for inspiration. Normal expiration is primarily a result of the diaphragm relaxing, and expiratory muscles do not contribute.
95) Cellular respiration refers to the intracellular reactions that consume oxygen and produce ATP. External respiration refers to the exchange of gases between the environment and the lungs, lungs and blood, blood and cells, and the transport of those gases.
96) The pleura is a double-walled sac that surrounds each lung. One wall clings to the lung surface, the other to the wall of the thoracic cavity. The pleura secretes and contains pleural fluid, which is a lubricant. Pleural fluid also keeps the wall of the lung in close proximity to the wall of the thoracic cavity, which is critical in the process of pulmonary ventilation.
97) Intrapulmonary pressure is the pressure inside the alveoli. Intrapleural pressure is the pressure within the pleural cavity. Intrapleural pressure variation drives variation inside the alveoli, but is always lower than atmospheric pressure, where pressure inside the alveoli equilibrates with atmospheric pressure during the respiratory cycle.
98) Surfactant, made by the type II alveolar cells, reduces the surface tension in the fluid in the alveoli, thereby facilitating inflation and inhibiting collapse of the alveoli.
99) The lungs are one of the last organs to develop during pregnancy and the type II alveolar cells are particularly late in developing. Since the type II alveolar cells secrete surfactant, premature babies may not make enough surfactant to reduce the resistance to breathing and may need positive pressure oxygen to be given along with surfactant to help them breathe on their own.
100) Dalton's law states that the total air pressure in a mixture of gases is the sum of the pressures contributed by each individual gases (the partial pressures). It is important because the air that we breathe is a mixture of gases, gas pressure is related to amount of gas, and the respiratory system is regulated in part by the partial pressures of oxygen and carbon dioxide in the body.
101) 1. Flow takes place from regions of higher pressure to regions of lower pressure.
2. A muscular pump creates pressure gradients.
3. Resistance to fluid flow is influenced primarily by the diameter of the tubes.
The primary difference is that air is a compressible mixture of gases while blood is a non-compressible liquid.
102) 1. It creates a moist, slippery surface so opposing membranes can slide across one another as the lungs move within the 2. It holds the lungs tight against the thoracic wall.
103) 1. The total pressure of a mixture of gases is the sum of the pressures of the individual gases (Dalton's law).
2. Gases, singly or in a mixture, move from areas of higher pressure to areas of lower pressure.
3. If the volume of a container of gas changes, the pressure of the gas will change in an inverse manner (Boyle's law).
4. The pressure and volume of a container of gas are directly related to the temperature of the gas and the number of molecules in the container: PV = nRT (the ideal gas law).
104) Since the air that Ali is breathing is not humidified (thus dry), large amounts of moisture are leaving the mucus to humidify the air that is being respired. This makes the mucus tacky and the cilia have difficulty moving. As more mucus is produced, it builds up, forming the nasal congestion in the morning. As Brad showers and drinks fluid, the moisture is replaced and the mucus loosens up and is moved along the proper route as usual. The reason this happens mostly at night is because Brad is probably not getting up frequently to drink water to replace what is being lost to humidify the air.
105) Unless the infant was suffocated immediately at birth, the first breath that it took would start to inflate the lungs and some of the air would be trapped in the lungs. By placing the lungs in water to see if they float or not, the medical examiner can determine whether or not there is any air in the lungs. Other measurements and tests could also be used to determine if the infant had breathed at all (air in the lungs) or was dead at birth (lungs collapsed and a small amount of fluid in the alveoli).
106) When breathing the compressed air from a SCUBA tank, the lungs are virtually completely inflated. Problems would arise if he held his breath and began to ascend. On ascending, the decrease in pressure would cause the gas in his lungs to expand (Boyle's law). Since the lungs are already fully inflated, this would cause over-inflation and possible rupturing of the lung. If this occurred, air would leak from the lungs into the pleural cavity, resulting in a pneumothorax and a collapsed lung.
107) Surfactant is necessary to reduce surface tension sufficient to prevent small or collapsed alveoli. Sherry needs to inhale more forcefully to get the same tidal volume, so lower intrapleural pressure would help.
108) Stimulation of beta receptors activates the sympathetic division, overriding the parasympathetic division. Increased heart rate, nervousness, nausea, and tremors all accompany sympathetic stimulation.
109) A. In both systems, fluids flow down a pressure gradient, within different-sized tubes of variable resistance; the pressure gradient is generated by the action of a muscular pump. In the cardiovascular system, the tubes vary from elastic arteries that minimize pressure extremes and fluctuations, muscular arteries and arterioles whose diameter is changeable to regulate flow and that account for most of the resistance, finally to the large number of tiny capillaries in parallel, with veins to conduct the blood back to the pump. In the respiratory system, the larger tubes are rigid and acco most of the resistance, and lead to a large number of tiny tubes in parallel whose diameter is adjusted to regulate flow.
B. In the closed cardiovascular system, the highest pressure is generated within the left ventricle, and an incompressible flows in a continuous fashion. High pressure is created when the ventricle contracts, squeezing the blood it contains; lo pressure results when the ventricle relaxes. In the open respiratory system, the highest pressure during normal breathing is generated when the respiratory muscles relax, decreasing the volume of the alveoli as air flows out; low pressure results when the muscles contract. Air is compressible, thus Boyle's law of inverse relationship between volum and pressure is important. The flow of air is intermittent, flowing into the lungs then stopping, and flowing out of the lu stopping again.
C. The driving pressure for fluid flow in the cardiovascular system is created directly by contraction of the heart chamb depends upon the total peripheral resistance. The driving pressure for fluid flow in the respiratory system is created indirectly by contraction of respiratory muscles, which produces a volume increase that creates a pressure decrease relative to atmospheric pressure. The compressibility of air and the incompressibility of blood, as well as the fact that the respiratory system is open and thus dependent on atmospheric pressure, while the cardiovascular system is closed and thus wholly responsible for pressure, explains these differences.
110) Each volume would be roughly reduced by half, because only one lung is functioning. The collapsed lung cannot be used for pulmonary ventilation until the damage to the pleura is repaired and the low intrapleural pressure and residual volume is reestablished.
111) The artificial respirator needs to alternate the pressure it generates between slightly higher than atmospheric pressure and slightly lower than atmospheric pressure. These pressure fluctuations are what the respiratory system normally produces; thus they should be safe for the respiratory structures. The lungs of the patient will passively inflate and deflate in response, and gas exchange at the alveoli will occur. The principle is the same with mouth-to-mouth respiration.
112) Ariana suffered an impact that increased her intrapleural pressure above normal, possibly by pushing her diaphragm upward, forcing her to expel some of her residual volume. With her alveoli smaller than normal, they are very difficult to inflate. The lack of broken ribs suggests that she does not have a pneumothorax. The air being blown into her nostrils has a higher PO2, which will increase the diffusion into her blood and compensate for her temporarily decreased tidal volume.
113) Alveolar ventilation = ventilation rate × (tidal volume - dead space volume). Julia's ventilation is 5432 mL/min, which is better than Lyle's, which is 3375 mL/min.
114) A. 14 breaths/min × 450 mL/breath = 6300 mL/min
B. Alveolar vent = 14 breaths/min × (450 mL/ breath - 150 mL dead space) = 14 breaths/min × 300 mL/breath = 4200 mL/min
115) Partial pressure = Patm × % gas in atmosphere.
A. 157.32 mm Hg oxygen, 594.32 mm Hg nitrogen, 3.04 mm Hg carbon dioxide
B. 342 mm Hg oxygen, 311.6 mm Hg nitrogen, 22.8 mm Hg carbon dioxide, 83.6 mm Hg hydrogen
C. 600.4 mm Hg oxygen, 114 mm Hg nitrogen, 38 mm Hg carbon dioxide, 7.6 mm Hg argon.
116) The resting graph should resemble Figure 17.7. During exercise, the only things that change are the size of the tidal volume curve, which will become larger as it enters into the inspiratory and expiratory reserve capacities, and these reserve capacities will have the same extreme values but will be smaller.
117) See Figure 17.9 in the chapter.
118) A. The snorkel tube effectively increases the total length of the respiratory passage, which increases the resistance to air flow (R Lη/r4); this makes Omar work harder to breathe. Resistance increases proportionally to L/r4; 40/1.24 = 19.
B. Dead space is the volume of air that enters the respiratory structures, but does not reach the alveoli and cannot contri gas exchange. The snorkel tube increases the amount of dead space by p 1.22 × 40 = 181 mL, which more than doubles t dead space to 331 mL. Alveolar ventilation = ventilation rate × (tidal volume - dead space) = 12/min × (500 mL - 331 mL) = 2028 mL/min; this is less than half of normal alveolar ventilation. To maintain 4200 mL/min, Omar could increase his ventilation rate to 25 breaths/min (4200/(500 - 331)). Alternatively, he could increase his ventilation depth to 681 mL/breath (4200/12 + 331). Or he could alter both rate and depth.
C. Tube 1: 60/1.24 = 29. Tube 2: 60/24 = 3.75. The first tube would require significantly more effort to use than the tube i A, so he would not be able to snorkel as long, if at all. The second tube sounds desirable, but dead space must be consid The snorkel tube adds an additional p 2 cm2 × 60 cm = 754 mL of dead space, which is greater than normal tidal volume and would reduce alveolar ventilation. Neither tube is practical.
119) D
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) High carbon dioxide concentration in body fluids is called
A) hyperoxia.
B) carbonation.
C) hypercapnia.
D) hypercarbia.
E) hyperdioxia.
2) The partial pressure of oxygen in arterial blood is approximately mm Hg.
A) 100 B) 45
50
70
3) The partial pressure of carbon dioxide in the cells of peripheral tissues is approximately mm Hg. A) 40
100
50
46
40
70
4) Of the factors that influence diffusion of respiratory gases, the most variable and, therefore, important factor to consider is the
A) membrane surface area.
B) concentration gradient.
C) electrical charge.
D) membrane thickness.
E) diffusion distance.
5) The process by which dissolved gases are exchanged between the blood and interstitial fluids is
A) pulmonary ventilation.
B) breathing.
C) diffusion.
D) cellular respiration.
E) external respiration.
6) The lung pathology most likely to result from certain kinds of heart disease is A) asthma.
B) emphysema.
C) pulmonary edema.
D) lung cancer.
E) fibrotic lung disease.
7) Hypoxia resulting from fluid accumulation in the alveoli that cannot be corrected by oxygen therapy can lead to
A) sudden infant death syndrome.
B) emphysema.
C) asthma.
D) adult respiratory distress syndrome.
E) fibrotic lung disease.
8) If the partial pressure of oxygen in both air and water is 100 mm Hg, then the concentration of the oxygen is the same in the air and water.
A) True B) False
9) The variables of oxygen consumption, cardiac output, and blood oxygen content are unrelated.
A) True B) False 9)
10) Which characteristic makes hemoglobin's structure such a good match for its function as an oxygen carrier?
A) Each hemoglobin molecule can bind one oxygen molecule.
B) Each hemoglobin molecule cannot be saturated by oxygen molecules.
C) Each hemoglobin molecule can bind two oxygen molecules.
D) Each hemoglobin molecule can bind four oxygen molecules.
E) Each hemoglobin binds irreversibly to an oxygen molecule.
11) Most of the oxygen transported by the blood is
A) carried by white blood cells.
B) bound to hemoglobin.
C) bound to a plasma protein.
D) in ionic form as solute in the plasma.
E) dissolved in plasma.
12) At a PO2 of 70 mm Hg and normal temperature and pH, hemoglobin is % saturated with oxygen.
25 B) 10
50
13) Which would make the oxygen-hemoglobin curve shift right?
A) increased H+ concentration
B) decreased CO2
C) increased pH
D) decreased temperature
E) None of the answers are correct.
14) Chronic hypoxia
A) can be caused by anemia.
B) increases 2,3-BPG production in blood.
C) shifts the HbO2 dissociation curve to the left.
75
D) increases 2,3-BPG production in blood and can result from anemia.
E) All of the answers are correct.
15) Most of the carbon dioxide in the blood is transported as A) solute dissolved in the cytoplasm of red blood cells.
B) carbonic acid.
C) carbaminohemoglobin.
D) bicarbonate ions.
E) solute dissolved in the plasma.
16) In the medulla oblongata, the nucleus tractus solitarius contains the of neurons.
A) dorsal respiratory group
C) pre-Botzinger complex
B) pontine respiratory group
D) ventral respiratory group
over 90
17) The most important chemical regulator of respiration is
A) carbon dioxide.
B) oxygen.
C) bicarbonate ion.
D) sodium ion.
E) hemoglobin.
18) An increase in the level of carbon dioxide in the blood will
A) increase the rate of breathing.
B) decrease the alveolar ventilation rate.
C) increase the pH of arterial blood.
D) decrease pulmonary ventilation.
E) decrease the rate of breathing.
19) The expiratory neurons control the muscles, whereas the inspiratory neurons control the muscles.
A) abdominal muscles and internal intercostals, diaphragm and external intercostals
B) diaphragm and abdominal muscles, internal and external intercostals
C) diaphragm and internal intercostals, abdominal muscles and external intercostals
D) diaphragm and external intercostals, abdominal muscles and internal intercostals
E) abdominal muscles and external intercostals, diaphragm and internal intercostals
20) If the neural connections between the pons and medulla are cut, breathing will stop.
A) True B) False
21) The Hering-Breuer reflex
A) alters pulmonary ventilation when the PO2 changes.
B) is an important aspect of normal, quiet breathing.
C) limiting ventilation volumes.
D) alters pulmonary ventilation when the PCO2 changes.
E) functions to increase ventilation with changes in blood pressure.
22) Protective reflexes of the lungs include
A) bronchodilation and coughing.
B) bronchodilation.
C) coughing.
D) bronchoconstriction.
E) coughing and bronchoconstriction.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the lung disease to its description.
23) destruction of alveoli
24) thickened alveolar membrane and decreased lung compliance
25) decreased surface area for gas exchange
26) increased airway resistance
27) fluid accumulation in interstitial spaces
28) increased diffusion distance
Match the factor with its effect on the affinity of hemoglobin for oxygen.
29) increased temperature
30) increased pH
increased PCO2 32) increased 2,3-BPG
increase
decrease
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 33) Too little oxygen in cells is called 33)
34) Too little oxygen in cells is often accompanied by too much , which is called 34) .
35) Generally, PO2 in arterial blood is than PO2 in venous blood. 35)
36) Generally, PCO2 in arterial blood is than PCO2 in venous blood. 36)
37) PCO2 tends to be in tissues than in systemic capillaries. 37)
38) Diffusion rate is directly proportional to , and 38)
39) is characterized by a decreased surface area for gas exchange in the lungs. 39)
40) is characterized by a thickened alveolar membrane, slowing respiratory gas exchange. 40)
41) In , fluid accumulates in the interstitial spaces of the lungs, slowing gas exchange. 41)
42) is characterized by an increased airway resistance and decreased ventilation. 42)
43) Diffusion rate is indirectly proportional to . 43)
44) is the enzyme that converts CO2 into bicarbonate ions. 44)
45) The group of neurons contains mostly inspiratory neurons. The group of neurons controls muscles used for active expiration and some inspiratory muscles. 45)
46) The output of the group of inspiratory neurons controls the muscle(s) by way of the nerve. 46)
47) Inappropriate relaxation of the muscles during sleep contributes to , a sleep disorder associated with snoring. 47)
48) Specialized in the carotid and aortic bodies are activated by a decrease in PO2 and pH or an increase in PCO2 What do they trigger? 48)
49) The carotid and aortic bodies contain specialized cells, which can increase ventilation in response to changes in PO2, PCO2, or pH. 49)
50) Fear and excitement may affect the pace and depth of respiration by stimulation of portions of the 50)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
51) What force(s) move(s) carbon dioxide from the blood into the alveoli?
52) List and explain the factors that influence gas diffusion in the lungs.
53) Name three pathological changes that adversely affect gas exchange.
54) List and explain the factors that influence the presence of gases in liquids.
55) What are the three ways CO2 is transported in blood? Approximately what percentage is transported by each way?
56) What are the PO2 and PCO2 in the alveoli, pulmonary artery, peripheral tissue, and systemic veins? Explain why the PO2 and PCO2 change.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
57) Mara lives in St. Louis, which is close to sea level. She decides to spend a month of her summer vacation working in the mountains outside of Denver. After a week in the mountains, what kinds of changes would you expect to see as Mara adapts to the higher altitude?
A) decreased PO2 in the alveoli
B) decreased alveolar ventilation rate
C) decreased hematocrit
D) decreased blood pressure
E) All of the answers are correct.
58) Carbon dioxide is more soluble in water than oxygen. To get the same amount of oxygen to dissolve in plasma as carbon dioxide, you would have to
A) decrease the partial pressure of nitrogen.
B) increase the rate of plasma flow through the lungs.
C) increase the partial pressure of oxygen.
D) decrease the alveolar ventilation rate.
E) decrease the temperature of the plasma.
59) For maximum efficiency in loading oxygen at the lungs,
A) the PO2 should be about 70 mm Hg.
B) BPG levels in the red blood cells should be high.
C) the pH should be slightly acidic.
D) the temperature should be slightly lower than normal body temperature.
E) All of the answers are correct.
60) A student in your lab volunteers to enter a hypoxic breathing chamber for 10 minutes, and his alveolar PO2 drops to 50 mm Hg. What other change would occur?
A) decrease in arterial pH
B) decrease in pH of cerebrospinal fluid
C) decrease in arterial PCO2
D) hypoventilation
E) increase in alveolar PCO2 60)
61) A inhibitor of carbonic anhydrase would
A) increase the amount of bicarbonate formed in the blood.
B) increase blood pH.
C) interfere with oxygen binding to hemoglobin.
D) decrease the amount of carbon dioxide dissolved in plasma.
E) All of the answers are correct.
62) The chloride shift occurs when
A) hydrogen ions leave the red blood cells. B) carbonic acid is formed.
C) bicarbonate ions leave the red blood cells. D) hydrogen ions enter the red blood cells. 62)
63) Blocking afferent action potentials from the chemoreceptors in the carotid and aortic bodies would interfere with the brain's ability to regulate breathing in response to all EXCEPT which changes?
A) changes in pH due to carbon dioxide levels
B) changes in PO2
C) changes in PCO2
D) changes in blood pressure
E) All of the answers are correct.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
64) Describe the different causes of hypoxia, and give specific examples of the associated conditions.
65) What are the two possible causes of lower alveolar PO2? Give examples of each.
66) Describe the problems that result in low arterial oxygen content.
67) Compare and contrast the pulmonary pathologies that affect alveolar ventilation and gas exchange.
68) Explain how oxygen and carbon dioxide are transported in the blood. How does the means of transport relate to the solubility and chemical reactivity of these gases in plasma?
69) List and describe the brain's centers for monitoring and controlling respiration.
70) List and describe the locations and stimuli for respiratory chemoreceptors.
71) Draw a flow chart that shows the steps of the reflex loop in which an increase in blood PCO2 leads to increased ventilation.
72) A 10-year-old swimmer has attached an extension to his snorkel tube, so that he can sit on the bottom of the ocean for a longer period of time, watching the fish of the coral reef. What problems would you expect him to have? Assuming he is successful in breathing this way for a little while, what are some of the differences he will experience compared to normal breathing?
73) Drowning often occurs when outside water enters the alveoli, yet some water is normally present in alveoli. Why is water normally present in the alveoli? What is present in alveolar fluid, besides water, that aids in respiration? What properties of water are harmful to respiration? What causes drowning? While extremely rare, there have even been documented cases of people walking away from recreational swimming only to die later, on dry land, as a result of drowning (termed "delayed" or "secondary" drowning). Propose an explanation for delayed drowning.
74) In the science fiction movie The Abyss, a diver is able to breathe while his head is in a specially prepared liquid pumped into a water-tight helmet attached to a suit, thus allowing him to dive without an air tank and at greater depths than possible for scuba divers. Is this purely fiction, or is it at least theoretically possible? Explain, thinking about the characteristics of alveoli and alveolar gas exchange. Assuming it is possible, describe the characteristics of the liquid in terms of its oxygen pressure and concentration.
75) Do the factors affecting affinity of hemoglobin for oxygen have the same effect on loading and unloading oxygen in lungs and tissues? Explain your answer, and indicate if this presents a conflict in responding to hypoxia. Assuming a medical team has treatments available for changing all the factors affecting hemoglobin's oxygen affinity, how should they change pH, temperature, PCO2, and 2,3-BPG content in a hypoxic patient?
76) Hemoglobin binds to and has a much higher affinity for carbon monoxide (CO) than for oxygen. CO is colorless and odorless and can be produced in homes heated by natural gas; victims usually do not realize they are being poisoned and often die in their sleep. Describe the likely changes in a CO poisoning victim.
77) Compare and contrast carbon monoxide (CO) poisoning, in which CO displaces oxygen from hemoglobin, and metabolic poisoning such as by cyanide.
78) Write the chemical equation catalyzed by the enzyme carbonic anhydrase. Suppose the concentration of H+ is increased by an outside force in a solution that had been at equilibrium. According to the law of mass action, what must happen to the CO2 concentration to reestablish equilibrium after this disturbance? What must happen to the concentration of bicarbonate?
79) A chemistry student accidentally spills chlorine bleach into a dilute acid. The mixture reacts and produces fumes that are inhaled by the student and that reduce his ventilation. Assume that the gaseous chemical produced is a base (i.e., it releases OH- in an aqueous solution), and that the chemical is absorbed into the bloodstream at the alveoli. Explain why ventilation is reduced in the patient.
80) You are a scientist who has been hired to write a screenplay for a popular TV series. The plot involves the discovery by a botanist of a plant toxin that interferes with the function of the exchange pump responsible for the chloride shift. This scientist provides the toxin to bioterrorists. What should you write for the coroner to say about symptoms in the poisoning victims?
81) Which is usually more important in regulating the respiratory system, PO2 or PCO2? Explain your answer and briefly discuss the receptors involved. Give examples of situations in which each of those factors changes enough to stimulate a reflex. How and why are these factors related to each other?
82) Timmy is a toddler who has just threatened that he will hold his breath until his mother gives him some chocolate. His mother refuses to be manipulated and watches as Timmy stubbornly refuses to breathe. To her horror, Timmy loses consciousness and collapses onto the floor. Her cousin, who is enrolled in a course for emergency medical technical (EMT) training, is visiting, and tells her there is no need to call for an ambulance. Why did Timmy lose consciousness? Should his mother trust her instincts and call for help and begin CPR, or should she listen to her well-meaning but young and inexperienced cousin? Explain.
83) Cary deliberately hyperventilates for several minutes before diving into a swimming pool. Shortly after he enters the water and begins swimming, he blacks out and almost drowns. What caused this to happen?
84) Define hyperventilation and explain what may cause it. Is the increased ventilation that occurs while exercising an example of hyperventilation? Explain your answer. How are PO2 and PCO2 affected by hyperventilation? Can breathing into a paper bag decrease hyperventilation? Explain.
85) Oxygen consumption increases with exercise due to the fact that the contracting muscles are doing work and req ATP to produce the contractions.
A. How does the body meet the increased demand for oxygen?
B. Calculate the oxygen consumption of a runner using the following information: Heart Rate: 130 bpm; Stroke Volume: 270 mL/beat; Arterial oxygen content: 250 mL O2/L blood, and Venous oxygen content: 100 O2/L blood.
86) The graph below shows an oxygen dissociation curve, with the normal curve in the center. What is the shift in th to the right called? What causes this change in oxygen dissociation? Is the shift helpful or harmful? Explain.
87) Refer to the graph below.
A. At a PO2 of 80 mm Hg, which type of hemoglobin binds more oxygen?
B. At a PO2 of 40 mm Hg, which type of hemoglobin has released more oxygen to the cell?
C. Explain the significance of the differences in fetal and maternal hemoglobin affinity.
D. If a worm lived in low oxygen mud flats where the PO2 is 60 mm Hg, which type of hemoglobin would be be for it to have? Explain.
Answer Key
Testname: UNTITLED37
1) C
2) A
3) D
4) B
5) C
6) C
7) D
8) B
9) B
10) D
11) B
12) E
13) A
14) D
15) D
16) A
17) A
18) A
19) A
20) B
21) C
22) E
23) C
24) D
25) C
26) B
27) A
28) A
29) B
30) A
31) B
32) B
33) hypoxia
34) carbon dioxide, hypercapnia
35) higher
36) lower
37) higher
38) the available surface area, the concentration gradient of the gas, the permeability of the barrier
39) Emphysema
40) Fibrotic lung disease
41) pulmonary edema
42) Asthma
43) square of the distance (membrane thickness)
44) Carbonic anhydrase
45) dorsal respiratory, ventral respiratory
46) dorsal respiratory, diaphragm (or intercostals), phrenic (or intercostal)
47) mouth and throat (larynx, pharynx, and tongue), obstructive sleep apnea
48) glomus cells
They trigger a reflex increase in ventilation.
49) glomus
50) limbic system
51) Carbon dioxide moves into the alveoli as a result of the pressure gradient.
52) Concentration gradient, surface area, membrane thickness, and diffusion distance are the four factors. Increasing the concentration gradient and surface area will increase the rate of diffusion across the lungs while increasing membrane thickness and diffusion distance will decrease the rate of diffusion in the lungs. This is discussed in the "Diffusion and Solubility of Gases" section of the chapter.
53) 1. a decrease in the amount of alveolar surface area available for gas exchange 2. an increase in the thickness of the alveolar membrane
3. an increase in the diffusion distance between the alveoli and the blood
54) Pressure, solubility, and temperature are three factors. This is discussed in "Gas Solubility Affects Diffusion" section of the chapter.
55) 1. attached to hemoglobin, 23%
2. dissolved, 7%
3. as bicarbonate, 70%
56) See Figure 18.2 and the "Gas Exchange in the Lungs and Tissues" section of the chapter.
57) A
58) C
59) D
60) C
61) B
62) C
63) D
64) See Table 18.1 in the chapter.
65) 1. The composition of the inspired air is abnormal. Altitude affects oxygen content of air.
2. Alveolar ventilation is inadequate. Pathological factors include increased airway resistance (asthma), decreased lung compliance (fibrosis), and overdoses of drugs or alcohol.
66) Three categories of problems are inadequacies in oxygen reaching alveoli, oxygen exchange between the alveoli and blood, and transport of oxygen in the blood.
67) See Figure 18.3(c) in the chapter, which discusses emphysema, fibrotic lung disease, pulmonary edema, and asthma.
68) Oxygen is not highly soluble in water, which is the main component of plasma. Less than 2% is dissolved in plasma, with the remainder bound to hemoglobin. The iron in the heme portion of the molecule can bind up to four oxygen atoms. Oxygen is not chemically reactive in the body. Carbon dioxide is more soluble than oxygen, at about 7% dissolved. Carbon dioxide is chemically reactive, combining with water to form carbonic acid, which then dissociates to bicarbonate and hydrogen ion. Most carbon dioxide is transported in the form of bicarbonate, about 70%, and the remaining 23% binds to amino acids on hemoglobin.
69) Respiratory neurons in the medulla control inspiration and expiration. Neurons in the pons modulate ventilation. The rhythmic pattern of breathing arises from a network of spontaneously discharging neurons. Ventilation is subject to modulation by various chemical factors and by higher brain centers.
70) Peripheral chemoreceptors in the carotid and aortic bodies sense changes in oxygen concentration, pH, and PCO2 of the plasma. Central chemoreceptors monitor cerebrospinal fluid composition and respond to changes in the concentration of CO2 in the cerebrospinal fluid.
71) Peripheral chemoreceptors in carotid and aortic bodies detect changes in PCO2 and pH. Central chemoreceptors in the medulla oblongata monitor CO2 in CSF. Either an increase in PCO2 or decrease in pH will stimulate the receptors, which project to a control center in the medulla oblongata. The control center stimulates somatic motor neurons that control the skeletal muscles involved in ventilation. The effect is increased ventilation, which lowers PCO2 by eliminating CO2, so blood pH increases because of this shift. See Figure 18.17 in the chapter.
72) The resistance to air flow increases as a result of adding the extension to the snorkel tube. Assuming he has used an extension of sufficiently large diameter, he is in a shallow location where the total length isn't excessive, and he has the strength and endurance in his respiratory muscles, he may be able to breathe this way for a few seconds longer than he could have held his breath. He will probably notice that he is breathing more deeply and at a higher rate, to maintain ventilation against the higher resistance. After a few exchanges he will start to hypoventilate, despite his efforts to increase pulmonary ventilation, because the presence of dead airspace in the tube will result in decreasing PO2 in the alveoli. Dead airspace is a problem if the total volume of air in the tube is greater than the volume exchanged with each breath.
73) Water is present everywhere in living tissues, because all living cells require water as a diffusion medium for solutes. Alveolar fluid is present in only a thin layer because it contains surfactant, preventing it from collapsing the alveoli due to surface tension. Oxygen has low solubility in water, but the large total surface area of alveoli combined with the thinness of the water layer in the alveoli allows for sufficient oxygen to enter the blood. Inhalation of water increases the amount of water and decreases the relative amount of surfactant. Less oxygen will reach the alveolar membranes, and alveoli will collapse. Alveolar collapse combined with the low solubility of oxygen in water will lead to hypoxemia and will trigger cardiovascular and respiratory reflexes. Delayed drowning likely results from tissue damage in the lungs and malfunction in other organs resulting from hypoxemia and reflexes related to the water inhalation.
74) (Note to instructor: Such experiments were done in the 1960s with rodents, and were partially successful but ultimately deemed impractical and too risky for humans.) It is theoretically possible. Oxygen dissolves in a thin film of fluid in the alveoli, thus even in normal breathing a liquid containing dissolved oxygen is involved. Obviously the respiratory gases would have to be soluble in this liquid and in concentrations appropriate to maintain the partial pressures necessary to drive diffusion.
75) Hemoglobin affinity changes in the same way in the lungs and tissues, thus increasing unloading in the tissues does decrease loading in the lungs, which seems as if one cancels out the other. But from the oxygen dissociation curves it is evident that the impact is greater in the tissues; thus increased unloading can remedy hypoxia. The medical team should decrease pH, increase temperature, increase PCO2, and increase 2,3-BPG.
76) CO will gradually displace O2 on hemoglobin molecules. While this increases O2 unloading in tissues, it will significantly decrease O2 loading in lungs, therefore hypoxia will result. Victims gradually lose consciousness as the brain tissues become hypoxic.
77) Both types of poisoning interfere with oxygen-dependent metabolism and thus can be fatal. CO prevents oxygen loading at the lungs and thus produces hypoxia. Metabolic poisons exert their effects on the chemical reactions that consume oxygen to produce ATP, and thus have no effect on PO2
78) CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3Carbon dioxide concentration will increase as the reaction is shifted to the left. Bicarbonate concentration will decrease.
79) The physiological response is opposite that for acidosis. A decreased ventilation would reduce loss of CO 2 By maintaining higher PCO2 in the blood, the resulting acidity would help to counteract the alkalinity resulting from the inhalation of a base.
80) The chloride shift is the transport process that occurs in red blood cells and is necessary for normal carbon dioxide transport. In this process, a bicarbonate ion is exchanged for a chloride ion. As a result, the red blood cell loses bicarbonate, which carries a negative charge, but gains a chloride ion, thus maintaining its membrane potential. Losing the bicarbonate prevents the chemical reaction that produces bicarbonate from carbon dioxide and water from reaching equilibrium. Bicarbonate is the most important extracellular buffer in the body. Without the transporter function, bicarbonate will build up inside the red blood cell and will not be maintained in the plasma. With a reduction in plasma bicarbonate, acidosis will result. An increase in pulmonary ventilation is triggered by acidosis and can help reverse this process, but it may be unable to compensate fully for the lack of bicarbonate buffer. Chapter 20 covers some of the physiological consequences of acidosis.
81) PCO2 is the more important factor. For PCO2, there are central and peripheral receptors that respond to CO2 as well as to CO2-related pH. These receptors are very sensitive to routine changes in PCO2 and pH, such as those associated with an increase in physical activity. Peripheral chemoreceptors have been identified for O2, but these respond only to dramatic changes in PO2, such as those associated with high altitude or disease. Because CO2 is produced as a by-product of aerobic (oxygen-consuming) metabolism, an increase in CO2 is associated with a corresponding decrease in O2.
82) Timmy loses consciousness due to hypoxia in his brain. There is no need for alarm, because the loss of consciousness indicates mainly that cerebral activity has decreased. The parts of the brain involved in respiratory control are in the brain stem. As long as Timmy was awake and determined, his cerebral signals were able to inhibit brain stem control of pulmonary ventilation. Once he loses consciousness, however, the respiratory control areas are released from inhibition and he starts breathing again. Soon normal oxygen content in the brain will be restored, and Timmy will wake up.
83) Hyperventilation causes a decrease in the alveolar PCO2, and more carbon dioxide is eliminated from the body than during normal breathing. The loss of large amounts of carbon dioxide upsets the body's normal drive for ventilation, and Cary does not feel the urge to breathe as he swims. As the exercising muscles use oxygen, a state of hypoxia develops. This results in insufficient amounts of oxygen reaching the brain, causing Cary to lose consciousness.
84) Hyperventilation is an increase in alveolar ventilation that exceeds metabolic demand. A person can deliberately hyperventilate, or it may occur as a result of emotional stress or high altitude. Strictly speaking, the increase in ventilation during exercise is necessary to meet increased metabolism and is therefore not hyperventilation. PO2 is increased and PCO2 is decreased during hyperventilation, because more O2 is inhaled and more CO2 is exhaled; this produces abnormally low PCO2 Hyperventilation can be remedied by a paper bag treatment, because rebreathing exhaled air will increase PCO2 in the body back to normal.
85) In order to meet the increased oxygen usage, more blood needs to be delivered to the working muscles. This is accompl increasing cardiac output and by vasodilation of blood vessels to the exercising muscles thus increasing flow and delive more oxygen rich blood. Oxygen consumption can be calculated using the Fick equation.
Qo2 = CO × (arterial oxygen content - venous oxygen content)
However, CO must be calculated first: CO = SV × HR = 130 × 250 = 32.5 L/min
Then Qo2 = 32.5 × (0.250 - 0.100) = 4.875 L O2/min
86) The shift in the dissociation curve is called the Bohr effect. The decrease in pH may be due to an increase in CO2 and lactic acid during vigorous physical activity, or to metabolic acidosis. The Bohr effect is helpful, because the unloading of oxygen from hemoglobin increases under such conditions. If the decrease in pH is due to exercise, then the skeletal muscles have an increased demand for oxygen, and thus increased unloading is desirable.
87) A. Fetal hemoglobin has a higher affinity for oxygen than maternal hemoglobin at that oxygen pressure.
B. Maternal hemoglobin releases oxygen more readily than fetal hemoglobin at that oxygen pressure.
C. The higher affinity of fetal hemoglobin for oxygen ensures a net transfer of oxygen from the maternal blood to the fet blood in the placenta. While unloading from fetal hemoglobin to fetal tissues is less favorable due to the higher affinity, rate of oxygen consumption in fetal tissues and consequent low oxygen pressure ensures unloading will occur.
D. The fetal form of hemoglobin would be better in this situation, because it has a higher affinity for the oxygen at this p Thus, the worm's blood would become more saturated, and more oxygen would then be available for the worm's cells.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Which is NOT a function of the kidneys?
A) regulation of extracellular fluid volume
B) maintenance of ion balance in body fluids
C) homeostatic regulation of blood pH
D) regulation of blood osmolarity
E) regulation of blood protein levels
2) Which ion is NOT directly regulated by the kidney?
A) Ca2+ B) HCO3- C) K+
3) The characteristic yellow color of urine is from the presence of
A) urobilinogen.
B) bile.
C) uric acid.
D) urea.
E) renin.
4) Urine is produced by the
A) gallbladder.
B) urethra.
C) kidney.
D) ureter.
E) urinary bladder.
5) Urine is carried to the urinary bladder by
A) lymphatics.
B) the ureters.
C) the urethra.
D) blood vessels.
E) All of the answers are correct.
6) Technically, the kidneys are located
A) in the pelvic cavity.
B) in the abdominal cavity.
C) behind the peritoneal membrane.
D) behind the pleural membranes.
E) in the thoracic cavity.
7) Blood flow through the kidney includes a feature seen in only a few organs. What is it?
A) arterial shunts
B) portal system
C) vascular sinuses
D) veins containing highly oxygenated blood
E) anastomoses
8) Which structure is NOT part of the blood circulation through the kidney?
A) glomerulus B) renal corpuscle C) vasa recta D) loop of Henle
9) Which statement is FALSE?
A) The urinary bladder is filled by two ducts, called ureters, and emptied by the single urethra.
B) Women are more likely to develop urinary tract infections than men.
C) The kidneys do not reabsorb filtered waste products.
D) The blood supply to the kidneys comes through the renal arteries.
E) As much as one fourth of the cardiac output may flow to the kidneys at any given moment.
10) The Bowman's capsule and glomerulus make up the
A) renal papilla.
B) renal corpuscle.
C) loop of Henle.
D) renal pyramid.
E) collecting system.
11) Which kidney process is always active and always requires energy to occur?
A) filtration B) secretion C) reabsorption D) excretion
12) A glomerulus is
A) the expanded end of a nephron.
B) a "ball" of capillaries within Bowman's capsule.
C) the hairpin-shaped segment of the nephron.
D) the portion of the nephron closest to the renal corpuscle.
E) the portion of the nephron that attaches to the collecting duct.
13) The portion of the nephron closest to the renal corpuscle is the
A) distal tubule.
B) minor calyx.
C) collecting duct.
D) proximal tubule.
E) loop of Henle.
14) The portion of the nephron that attaches to the collecting duct is the
A) distal tubule.
B) collecting duct.
C) proximal tubule.
D) minor calyx.
E) loop of Henle. 14)
15) The hairpin-shaped segment of the nephron is the
A) distal tubule.
B) minor calyx.
C) proximal tubule.
D) loop of Henle.
E) vasa recta.
16) The segment of the nephron between the proximal and distal tubules that loops down into the medulla of the kidney and returns back to the cortex is called the
A) collecting duct.
B) minor calyx.
C) Bowman's capsule.
D) loop of Henle.
E) vasa recta.
17) The process of filtration in the kidney is most accurately described as A) relatively nonspecific. B) highly specific. C) completely nonspecific.
18) Which is NOT normally be found in the filtrate?
A) erythrocytes. B) potassium. C) urobilinogen. D) glucose.
19) Cysts on the kidney can press upon nephrons, increasing the pressure inside the nephrons. How will this affect glomerular filtration rate and blood pressure?
A) GFR increases and blood pressure decreases
B) GFR decreases and blood pressure increases
C) GFR increases and blood pressure increases
D) GFR decreases and blood pressure decreases
20) The amount of plasma that filters into the nephrons is approximately of the total volume.
A) 1/5 B) 90% C) 4/5 D) 3/4 E) 1/2
21) In normal kidneys, blood cells and plasma proteins are
A) filtered and secreted.
C) secreted then reabsorbed.
22) Which is NOT a kidney filtration barrier?
A) juxtaglomerular apparatus
C) glomerular capillary endothelium
23) The force for glomerular filtration is the
B) filtered then reabsorbed.
D) not filtered.
B) basement membrane
D) Bowman's capsule epithelium 22)
A) fluid pressure produced by the displacement of the fluid in the lumen of the tubules.
B) ATP-dependent processes in the nephron.
C) blood pressure in the glomerular capillaries.
D) osmotic pressure in the glomerular capillaries.
E) None of the answers are correct. 23)
24) The primary function of the proximal tubule is
A) secretion of acids and ammonia.
B) adjusting the urine volume.
C) secretion of drugs.
D) reabsorption of ions, organic molecules, and water.
E) filtration.
25) Contents in the peritubular capillaries are actively transported into proximal and distal convoluted tubules in a process known as
A) secretion. B) filtration. C) excretion. D) reabsorption.
24)
25)
26) Glucose and amino acids are reabsorbed by
A) cotransport.
C) symport with sodium.
27) Which statement about autoregulation is TRUE?
B) countertransport.
D) diffusion.
A) In myogenic response, the macula densa cells send a paracrine message to the neighboring afferent arteriole.
B) Myogenic response is the intrinsic ability of vascular smooth muscle to respond to pressure changes.
C) Myogenic response is a paracrine signaling mechanism.
D) In tubuloglomerular feedback, stretch-sensitive ion channels open, resulting in depolarization of smooth muscle cells.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match each step in urine formation to its description.
28) movement from the nephron lumen to the external environment
29) movement from the nephron lumen to the blood
30) movement from the glomerulus to the nephron lumen
31) movement from the peritubular capillaries to the nephron lumen
A) secretion
B) excretion
C) reabsorption
D) filtration
Match each substance with its primary mode of transport across the kidney epithelium
32) sodium
33) glucose
34) urea
35) small plasma proteins
A) symport with a cation
B) passive reabsorption/diffusion
C) transcytosis
D) active transport
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
36) After it is formed, urine is temporarily stored in the 36)
37) Urine is carried to the external environment by the 37)
38) The plasma concentration at which all of the renal carriers for a given substance are saturated is the 38)
39) The amount of filtrate entering Bowman's capsule each minute is the 39)
40) The percentage of total plasma volume that filters is called the 40)
41) When fluid flow through the distal tubule increases as a result of increased GFR, the macula densa cells send a chemical message to the neighboring afferent arteriole. The afferent arteriole constricts, increasing resistance and decreasing GFR. This type of autoregulation involving both the kidney tubule and the arteriole is known as
42) The branch off the and supply blood to the kidneys. 42)
43) The carry blood from the kidneys back to the 43)
44) Eighty percent of the nephrons in a kidney are contained within the , but the other 20%, called the nephrons, dip down into the 44)
45) The are the long peritubular capillaries that dip into the medulla. 45)
46) The nephron begins with a hollow, ball-like structure called 46)
47) The lie between and around the glomerular capillaries. 47)
48) The specialized cells found in the capsule epithelium are called . These cells have long cytoplasmic extensions called . 48)
49) Neural control of GFR is mediated by that innervate receptors on vascular smooth muscle causing . 49)
50) The excretion of glucose in the urine is called . 50)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
51) Place the following blood vessels that carry blood to and within the kidney in the order in which blo passes through them.
1. afferent arteriole
2. efferent arteriole
3. glomerulus
4. peritubular capillary
52) When the plasma concentration of a substance exceeds its renal concentration, more of the substance will be
A) secreted.
B) filtered.
C) excreted.
D) reabsorbed.
E) None of the answers are correct.
53) Damage to the renal medulla would interfere first with the functioning of the
A) Bowman's capsule.
B) glomerulus.
C) collecting ducts.
D) distal tubule.
E) proximal tubule.
54) An obstruction in a glomerulus would affect the flow of blood into the A) renal vein.
C) afferent arteriole.
55) If blood flow through the afferent arterioles increases,
B) renal artery.
D) efferent arteriole.
A) stretch stimulates vasoconstriction to reduce the flow.
B) the smooth muscle in the vessel walls stretches to accommodate the increased flow and the stretch stimulates further relaxation of the arteriolar wall, lessening blood pressure.
C) the smooth muscle in the vessel walls stretches to accommodate the increased flow.
D) the stretch stimulates further relaxation of the arteriolar wall, lessening blood pressure. 55)
56) Urea is
A) completely eliminated in the urine.
B) actively transported into the filtrate by the cells of the collecting duct.
C) actively secreted in the distal tubule.
D) passively reabsorbed in the proximal tubule.
E) actively reabsorbed in the proximal tubule.
57) In the lumen of the proximal tubule, Na+ concentration is the Na+ concentration inside the cells of the tubule wall.
A) much higher than
B) much lower than
C) slightly lower than
D) slightly higher than
E) about the same as
58) The basic pattern for many molecules absorbed by Na+-dependent transport involves this: an apical and a basolateral
A) symport protein, osmotic gradient
B) facilitated diffusion carrier, osmotic gradient
C) facilitated diffusion carrier, symport protein
D) symport protein, facilitated diffusion carrier
E) osmotic gradient, symport protein
59) One substance has no membrane transporters to move it but can diffuse freely through open leak channels if there is a concentration gradient. Initially, this substance's concentrations in the filtrate and extracellular fluid are equal. Later, however, the active transport of Na+ and other solutes creates a gradient by removing water from the lumen of the tubule where it is located. What substance is this?
A) glucose
B) urea
C) calcium
D) glucose and calcium
E) glucose, calcium, and urea
60) Measurements in a nephron reveal a glomerular hydrostatic pressure of 69 mm Hg, and a fluid pressure in the Bowman's capsule of 15 mm Hg. Assuming that the plasma colloid osmotic pressure is 30 mm Hg, and that essentially no plasma proteins are filtered by the glomerulus, what is the net glomerular filtration pressure in this case?
A) 114 mm Hg
B) 84 mm Hg
C) 54 mm Hg
D) -6 mm Hg
E) 24 mm Hg
61) In a normal kidney, which condition would increase glomerular filtration rate (GFR)?
A) a decrease in the net glomerular filtration pressure
B) a decrease in the hydrostatic pressure of the glomerulus
C) an increase in the hydrostatic pressure in Bowman's capsule
D) constriction of the afferent arteriole
E) a decrease in the concentration of plasma proteins in the blood
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
62) A person with cirrhosis of the liver has lower than normal levels of plasma proteins and a higher than normal GFR. Explain why a decrease in plasma protein concentration would cause an increase in GFR.
63) Patrick's urine sample reveals a high concentration of glucose. Is glucose normally present in urine? Suggest two possible mechanisms to explain why the kidney would excrete excess glucose, and what abnormality may underlie those conditions.
64) Trace a drop of water through the urinary system, beginning with the plasma in the renal artery.
65) List and describe the three filtration barriers that substances leaving the plasma must pass through before entering the tubule lumen.
66) List and summarize the forces that influence filtration across the walls of glomerular capillaries.
67) Reabsorption involves which two methods of transport? Describe each. What determines which route a solute will take?
68) Describe GFR autoregulation, and explain why it is important.
69) Ruby is 77 years old and can no longer control her urination. What changed in the reflex pathway that used to control her urination?
70) Sylvia is suffering from severe edema in her arms and legs. Her physician prescribes a diuretic (a substance that will increase the volume of urine produced). Why might this help to alleviate Sylvia's problem?
71) Make a map of the following terms: blood, Bowman's capsule, collecting duct, distal tubule, excretion, external environment, filtration, loop of Henle, lumen, osmosis, peritubular capillaries, proximal tubule, urine, water. Add terms as needed.
72) A professor gave the following analogy of kidney function to his freshman biology class: "Imagine your desk is a disorganized mess, containing things worth keeping and things you should throw out. Instead of picking through each item one by one and considering if it is to keep or throw out, you sweep your arm across your desktop in one smooth motion, knocking the entire contents of the desk into your large trash can. Then you pull the items you want to keep out of the trash can and place them back on your desk." In what ways is this analogy accurate? In what ways is it inaccurate? Some students in his class argue that the kidneys are inefficient and poorly designed. How should the professor respond? What modern medical device may he cite in his response?
73) Presence of glucose in the urine is evidence of what condition?
74) Armann weighs 100 kg. Assume his total blood volume is 7%, his heart pumps his total blood volume within 90 seconds, and his renal blood flow is 20% of his cardiac output. Calculate the volume of blood that flows through Armann's kidneys each minute.
75) You are a physiologist on a space flight to a distant planet. You discover intelligent human-like aliens on the planet. You discover that the alien's kidney handles the sugar alcohol mannitol just like our kidneys handle inuli also test the alien for its renal handling of glucose. The data from that experiment are: Plasma level (constant ove hrs): 6 g/dL of mannitol and 2 g/dL of glucose; 24 hr. urine sample: volume of 2 L, containing 144 g mannitol and glucose.
A. What is the alien's glomerular filtration rate?
B. What is the alien's clearance rate for glucose?
C. How does the alien kidney handle glucose?
76) A man's leg was crushed between a car bumper and a wall. His physicians believe their patient has suffered kid damage from myoglobin blocking glomerular pores. Tests showed the following results: plasma creatinine: 30 mg/100 mL plasma 24 hour urine specimen: volume = 1 liter urine creatinine: 30 mg/mL urine
A. How many mg of creatinine are in the urine specimen? How much creatinine appears in the urine per hour?
B. What is the patient's creatinine clearance in mL/min?
C. What is the patient's GFR?
D. Is this a normal GFR? Did the patient sustain kidney damage?
Testname: UNTITLED38
1) E
2) D
3) A
4) C
5) B
6) C
7) B
8) D
9) C
10) B
11) B
12) B
13) D
14) A
15) D
16) D
17) A
18) A
19) B
20) A
21) D
22) A
23) C
24) D
25) A
26) C
27) B
28) B
29) C
30) D
31) A
32) D
33) A
34) B
35) C
36) urinary bladder
37) urethra
38) renal threshold
39) GFR or glomerular filtration rate
40) filtration fraction
41) tubuloglomerular feedback
42) renal arteries, abdominal aorta
43) renal veins, inferior vena cava
44) cortex, juxtamedullary, medulla
45) vasa recta
46) Bowman's capsule
47) mesangial cells
48) podocytes, foot processes
49) sympathetic neurons, alpha (or α), vasoconstriction
50) glucosuria or glycosuria
51) A
52) C
53) C
54) D
55) A
56) D
57) A
58) D
59) B
60) E
61) E
62) The primary driving force for GFR is blood pressure, opposed by fluid pressure in Bowman's capsule and osmotic pressure due to plasma proteins. If a person has fewer plasma proteins due to liver disease, the plasma will have a lower osmotic pressure. With less osmotic pressure opposing the GFR, GFR will increase.
63) Glucose transporters may be saturated, preventing complete reabsorption of glucose (filtration exceeds reabsorption). This can happen with extremely high glucose ingestion or with untreated diabetes mellitus. A genetic defect resulting in an insufficient number of glucose transporters is another possibility.
64) Plasma in the renal artery flows into smaller branches, entering the arcuate arteries, which lead to the afferent arterioles, which in turn lead to the glomeruli. Water moves from glomeruli into the nephrons (PCT, loop of Henle, then DCT), into the collecting ducts, then renal calyces and into the renal pelvis, passes into a ureter, then to the urinary bladder; finally, it is expelled as urine through the urethra.
65) 1. the glomerular capillary endothelium
2. a basal lamina
3. the epithelium of Bowman's capsule
See the "The Renal Corpuscle Contains Filtration Barriers" section of the chapter.
66) 1. hydrostatic pressure
2. colloid osmotic pressure
3. hydrostatic fluid pressure
See the "Capillary Pressure Causes Filtration" section of the chapter.
67) 1. transepithelial transport: substances cross both apical and basolateral membranes of the tubule epithelial cell.
2. paracellular pathway: substances pass through the junction between two adjacent cells.
The permeability of the epithelial junction and the electrochemical gradient for the solute determines which route it wil
68) 1. The myogenic response is the ability of the vascular smooth muscle to constrict or dilate to keep pressure and flow co thereby keeping GFR constant. Vasoconstriction is more effective at this than vasodilation.
2. Tubuloglomerular feedback involves production of a paracrine, in response to increased GFR, which constricts the af arteriole to decrease GFR. Autoregulation helps protect the filtration barriers from high blood pressures that could dam them.
69) Micturition normally occurs when stretch receptors in the bladder wall are stimulated by distension due to the accumulation of urine. The stretch receptors project to an integration center in the spinal cord, which stimulates parasympathetic neurons of the bladder wall, which stimulates bladder contraction, forcing the internal urethral sphincter to open. At the same time, the spinal control center inhibits somatic motor neurons that control the external urethral sphincter, which relaxes in response, so that urine can flow out. The spinal reflex is normally overridden by descending control from the brain stem and cerebral cortex. The brain inhibits the parasympathetic output to the bladder and stimulates the somatic motor output to the external urethral sphincter, thus preventing urination until a convenient time. It is likely that Ruby's descending control is what is no longer working properly; thus she is not able to suppress the urge until she can get to a toilet.
70) One simple answer is that a diuretic reduces the free fluid in the body. A more complex explanation is that increasing the volume of urine produced would decrease the total blood volume of the body. This in turn would lead to a decreased blood hydrostatic pressure. Edema is frequently the result of hydrostatic pressure of the blood exceeding the opposing forces at the capillaries in the affected area. Depending on the actual cause of the edema, decreasing the blood hydrostatic pressure would decrease edema formation and possibly cause some of the fluid to move from the interstitial space back to the blood. Diuresis would also increase the concentration of the proteins in the plasma, contributing to the fluid's movement out of the tissues and into the blood.
71) Maps will vary. See Figure 19.2 and the "Overview of Kidney Function" section of the chapter.
72) His analogy is accurate in that the glomerulus does dump contents into the nephron that the body needs and will take back. His analogy is inaccurate in that the entire contents of the plasma are not dumped, rather about 1/5 of the volume enters the nephron. While one could easily imagine a more efficient way to remove waste from the blood, the kidneys can only use the tools they have, namely various membrane transport processes and the physical laws governing movement of water and solutes. Kidney dialysis machines rely on diffusion through semipermeable membranes, mimicking part of normal kidney function.
73) Diabetes mellitus
74) Armann's blood volume = 100 kg × 0.07 = 7 L = 7000 mL. At least two thirds of this volume must circulate per minute = 7000 mL × 0.67 = 4690 mL/min minimum cardiac output (CO); values up to 5000 mL/min would still be within a normal range; 4690 × 20% = 938 mL/min; 5000 × 20% = 1000 mL/min, thus blood flow to Arman's kidneys approximates 938-1000 ml/min.
75) Human kidneys filter inulin, a polysaccharide from dahlia roots, but do not reabsorb or secrete it. Thus, 100% of the inu urine sample is filtered inulin. For this reason, the inulin excretion rate is the same as the glomerular filtration rate.
A. The alien's GFR = excretion rate of mannitol/plasma concentration of mannitol = 144 g/day × 1 dL/6 g × 0.1 L/1 dL = 2.4 L/day.
B. Using 2.4 L/day as GFR, the filtered load for glucose = plasma concentration of glucose × GFR = 2 g/dL × 2.4 L/day × 1 dL/0.1 L = 48 g glucose.
C. There were 52 g of glucose produced in 24 hours. Since the clearance of glucose is greater than the filtered load, some must have been secreted. Therefore the alien's kidney filters and secretes glucose.
76) A. 1000 mL urine × 30 mg creatinine/mL urine = 30,000 mg creatinine in the specimen. 30,000 mg/24 hr = 1250 mg creatinine.
B. Creatinine clearance = excretion rate of creatinine/plasma concentration creatinine. clearance = 1250 mg creatinine/hr × 1 hr/60 min/30 mg creatinine/100 mL plasma
= 20.8 mg creatinine/min/0.3 mg creatinine/mL plasma
= 69.4 mL plasma/min
C. GFR approximately equal to clearance rate for creatinine, or approximately 70 mL/min.
D. A more typical value for GFR is 125 mL/min, so 70 mL/min represents a severe decline. Thus, kidney damage has mo occurred.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) The primary route for water loss from the body is the system.
A) respiratory
B) digestive
C) cardiovascular
D) integumentary
E) urinary
2) The primary route for ion loss from the body is the system.
A) urinary
B) integumentary
C) digestive
D) respiratory
E) cardiovascular
3) Cell volume (and therefore cell function) in most cells is dependent upon careful regulation of
A) osmolarity of extracellular fluid.
B) volume of extracellular fluid.
C) permeability of cell membranes.
D) blood pressure.
E) resting membrane potential.
4) The two organ systems that work together to regulate most aspects of the body's water balance are
A) urinary and cardiovascular.
B) urinary and respiratory.
C) digestive and cardiovascular.
D) digestive and respiratory.
E) cardiovascular and respiratory.
5) Kidneys respond relatively to changes in blood volume. A) quickly B) slowly
6) Shrinkage of hepatocytes in the liver results in which of the following?
A) protein synthesis only
B) glycogen production only
C) glycogen breakdown only
D) both glycogen production and protein synthesis
E) both glycogen breakdown and protein breakdown
7) Most body water is located in
A) lumens of organs open to the outside. B) cells.
C) plasma. D) interstitial fluid.
8) Kidneys regulate
A) water gain only.
B) water loss only.
C) both water loss and gain.
9) When a body is dehydrated, water in the urinary bladder
A) can be returned to the circulation after moving back into the kidneys.
B) will still be expelled from the body in the urine.
C) can be returned to the circulation directly.
10) Water reabsorption by the kidneys is a result of
A) exchange with ions.
B) both passive and active transport processes.
C) osmosis.
D) cotransport with ions.
11) The hormone that directly controls water reabsorption by the kidneys is
A) angiotensin.
B) vasopressin.
C) aldosterone.
D) ANP.
E) epinephrine.
12) The hormone that regulates water reabsorption by the kidneys
A) only increases water permeability in certain portions of the kidney tubules.
B) decreases water permeability throughout the kidney tubules.
C) only decreases water permeability in certain portions of the kidney tubules.
D) increases water permeability throughout the kidney tubules.
13) Why do patients taking loop diuretics need to take supplemental potassium?
A) They inhibit the reabsorption of potassium as well as sodium in the loop of Henle.
B) They cause active reabsorption of potassium in the distal convoluted tubule.
C) They inhibit intestinal absorption of potassium.
D) They cause active secretion of potassium in the loop of Henle.
14) The primary osmoreceptors are located in the
A) medulla.
B) hypothalamus.
C) pons.
D) stomach.
E) kidney.
15) Osmoreceptors fire after they in response to plasma osmolarity.
A) swell, increased
C) shrink, increased
B) shrink, decreased
D) swell, decreased
16) The hormone vasopressin
A) stimulates the kidneys to retain water.
B) stimulates the kidneys to produce a large volume of urine.
C) stimulates the kidneys to retain sodium ions.
D) is secreted by the anterior pituitary gland in response to changes in blood osmolarity.
E) All of the answers are correct.
17) When venous return is increased, stretch receptors in the atria of the heart are activated. This results in
A) increased vasopressin secretion.
B) increased thirst.
C) decreased urine production.
D) decreased vasopressin secretion.
E) increased glomerular filtration.
18) When baroreceptors in the carotid and aortic bodies sense increased blood pressure, this results in
A) increased thirst.
B) increased glomerular filtration.
C) decreased urine production.
D) decreased vasopressin secretion.
E) increased vasopressin secretion.
19) Why is sodium actively reabsorbed in the nephron?
A) to increase passive reabsorption of water B) to decrease blood pressure
C) to make urine less concentrated
20) Granular cells secrete
A) aldosterone.
B) renin.
C) angiotensinogen.
D) angiotensin converting enzyme.
E) angiotensin I.
21) ACE converts
A) angiotensinogen to angiotensin I.
B) angiotensin II to aldosterone.
C) renin to aldosterone.
D) renin to angiotensinogen.
E) angiotensin I to angiotensin II.
22) Stimuli for the activation of the RAS pathway include
D) to decrease osmolarity inside the nephron
A) low blood pressure in arterioles in the nephron only.
B) low blood pressure in arterioles in the nephron and a decrease in fluid flow through the distal tubule.
C) a decrease in fluid flow through the distal tubule only.
D) high blood pressure in the renal artery only.
E) low blood pressure in arterioles in the nephron, a decrease in fluid flow through the distal tubule, and high blood pressure in the renal artery.
23) Angiotensin II stimulates
A) thirst, vasoconstriction, and release of aldosterone.
B) thirst only.
C) vasoconstriction only.
D) release of aldosterone.
E) thirst and vasoconstriction.
24) Which is FALSE about angiotensin II?
A) stimulates thirst
B) stimulates vasoconstriction
C) activates parasympathetic output
D) increases blood pressure
E) increases cardiac output
25) Drugs that treat hypertension by preventing Angiotensin I from becoming Angiotensin II are called
A) ACE inhibitors.
C) beta blockers.
26) Aldosterone
A) functions in pH regulation.
B) helps decrease blood volume.
B) calcium channel blockers.
D) diuretics.
C) stimulates sodium reabsorption in kidney principal cells.
D) increases the concentration of sodium in urine.
E) is secreted in response to increased levels of sodium in the blood.
27) Atrial natriuretic peptide
A) inhibits release of renin.
B) increases GFR and inhibits release of renin.
C) increases GFR and stimulates release of renin.
D) increases GFR.
E) stimulates release of renin.
28) An increase in plasma potassium levels is properly called
A) hypernatremia.
B) hyperkalemia.
C) hypercalcemia.
D) hyperpotassemia.
E) hyperpotasseplasmia.
29) Excess potassium ions are eliminated from the body by the
A) sweat glands.
B) liver.
C) spleen.
D) kidneys.
E) digestive system.
30) Thirst is
A) controlled by centers in the hypothalamus, stimulated by increased osmolarity, and relieved only when plasma osmolarity is decreased.
B) controlled by centers in the hypothalamus.
C) stimulated by decreased osmolarity.
D) relieved only when plasma osmolarity is increased.
E) controlled by centers in the hypothalamus and stimulated by increased osmolarity.
31) A hormone that helps to regulate the sodium ion concentration of the blood is
A) cortisol.
B) somatotropin.
C) parathormone.
D) thymosin.
E) aldosterone.
32) Which about the hormone atrial natriuretic peptide is FALSE?
A) increases sodium loss at the kidneys
B) decreases blood pressure
C) increases aldosterone secretion
D) produced by cells in the heart
E) decreases vasopressin secretion
33) The enzyme renin is responsible for the production of
A) atrial natriuretic peptide.
B) erythropoietin.
C) angiotensinogen.
D) angiotensin I.
E) cortisol.
34) Angiotensin I is converted to angiotensin II by enzymes primarily located in the A) heart.
C) kidneys.
B) lungs and blood vessels.
D) liver. 34)
35) The osmolarity in the bottom of the loop of Henle is mOsM.
A) 100
B) 900
C) 300
D) 1200
E) None of these answers are correct. 35)
36) Decreased ECF volume causes
A) the force of ventricular contraction to decrease.
B) sympathetic output from the cardiovascular control center to increase and arteriolar vasodilation.
C) sympathetic output from the cardiovascular control center to increase.
D) parasympathetic output from the cardiovascular control center to increase.
E) arteriolar vasodilation. 36)
37) Symptoms of low plasma pH may include
A) CNS depression only.
B) CNS depression and confusion and disorientation.
C) CNS depression; confusion and disorientation; and numbness, tingling, or muscle twitches.
D) confusion and disorientation only.
E) numbness, tingling, or muscle twitches only.
38) The most important factor affecting the pH of plasma is the concentration of
A) hydrochloric acid.
B) carbon dioxide.
C) lactic acid.
D) ketone bodies.
E) organic acids.
39) The primary role of the carbonic acid-bicarbonate buffer system is to
A) buffer carbonic acid formed by carbon dioxide.
B) buffer stomach acid.
C) buffer the urine.
D) increase the amount of carbonic acid during ventilation.
E) prevent pH changes caused by organic and fixed acids.
40) Which is most likely to be observed in a patient with compensated respiratory alkalosis?
A) respiratory rate increases
B) kidneys reabsorb more hydrogen ions
C) kidneys conserve bicarbonate
D) body keeps less carbon dioxide
E) tidal volume increases
41) Vomiting of the stomach's contents can cause
A) metabolic alkalosis.
B) respiratory alkalosis.
C) respiratory acidosis.
D) metabolic acidosis.
E) None of the answers are correct.
42) Emphysema can cause
A) respiratory acidosis.
B) metabolic alkalosis.
C) metabolic acidosis.
D) respiratory alkalosis.
E) None of the answers are correct.
43) Hyperventilation can cause
A) metabolic alkalosis.
B) respiratory alkalosis.
C) respiratory acidosis.
D) metabolic acidosis.
E) None of the answers are correct.
44) If sodium increases in the ECF, water will move from A) the ECF to cells, and cells will shrink. B) cells to the ECF, and cells will shrink. C) the ECF to cells, and cells will swell. D) cells to the ECF, and cells will swell.
45) A buffer
A) always decreases pH.
B) always increases pH. C) binds or releases bicarbonate ions. D) moderates changes in pH.
46) The normal pH range for most body fluids is
A) 7.25 to 7.75. B) 7 to 8.
45)
C) 7.5 to 8. D) 7.38 to 7.42. 46)
47) When the pH rises above 7.42, a state of exists. A) equilibrium B) alkalosis C) homeostasis D) acidosis
48) Abnormal fat and amino acid metabolism may lead to the condition called A) ketoacidosis.
B) respiratory acidosis. C) lactic acidosis. D) metabolic alkalosis.
47)
48)
49) The enzyme that catalyzes the conversion of H2O and CO2 to H2CO3 is called A) carbonic anhydrase. B) carbonic acid. C) renin. D) bicarbonate ion. 49)
50) Normal removal of excess water in urine is known as
A) diuretics.
C) filtration.
B) osmotic diuresis.
D) diuresis.
51) interstitial osmolarity allows urine to be concentrated.
A) Low medullary
C) High medullary
B) High cortex
D) Low cortex
52) AQP2 water pores are added to the cell membrane by and withdrawn by in a process known as
A) membrane recycling, endocytosis, exocytosis
B) membrane recycling, exocytosis, endocytosis
C) endocytosis, exocytosis, membrane recycling
D) exocytosis, endocytosis, membrane recycling
53) The anatomical arrangement of the kidney that allows transfer of solutes from one blood vessel to another is called the
A) countercurrent exchange system.
C) countercurrent heat exchanger.
B) portal system.
D) capillaries. 53)
54) Paracrine feedback from the in the distal tubule to the granular cells stimulates release of
A) granular cells, renin
C) liver, angiotensinogen
B) sympathetic neurons, epinephrine
D) macula densa, renin 54)
55) The cells of the distal nephron are interspersed among the principal cells and contribute to acid-base regulation.
A) endothelial B) intercalated C) granular D) endocrine
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
56) How do kidneys control urine concentration? 56)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
57) Increased angiotensin II levels would result in increased
A) blood volume.
B) retention of water.
C) retention of sodium ions at the kidney.
D) blood pressure.
E) All of these effects.
58) The RAS pathway begins with secretion of A) renin.
B) aldosterone.
C) angiotensin converting enzyme.
D) vasopressin.
E) angiotensinogen. 58)
59) Renal tubule cells in the kidney medulla are constantly exposed to high extracellular osmolarity. How do they maintain normal cell volume?
A) They synthesize organic solutes as needed to match the osmolarity.
B) They maintain a water-impermeable membrane.
C) They add or remove aquaporins as needed.
D) They synthesize water molecules through increased metabolism to offset volume loss. 59)
60) When the pH of body fluids decreases, proteins will
A) lose three-dimensional structure.
C) become more active.
B) fold into tertiary structures.
D) not be affected.
61) When the pH of the extracellular fluid decreases, the kidneys
A) reabsorb more potassium ions.
B) excrete more sodium ions.
C) excrete more bicarbonate ions.
D) reabsorb more hydrogen ions.
E) reabsorb less water. 61)
62) Two hours before major surgery, the patient is stressed, with increased heart rate and blood pressure. These symptoms are the result of
A) increased parasympathetic activity.
B) sympathetic activation.
C) decreased activity of sympathetic centers in the hypothalamus.
D) decreased levels of epinephrine in the blood.
E) All of these mechanisms. 62)
63) An explorer has been lost in the desert for two days with very little water. As a result, you would expect to observe
A) cells enlarged with fluid.
B) increased vasopressin levels.
C) increased blood volume.
D) normal urine production.
E) decreased blood osmolarity.
64) Which effect would a decrease in pH have on the amount of potassium ion in the urine?
A) increase B) decrease C) no effect
65) In response to a rapid increase of organic acid in the body, you would expect to observe
A) decreased heart rate.
C) increased blood pH.
B) increased alveolar ventilation.
D) decreased blood pressure.
66) Dehydration may cause some ions to become concentrated. If a person was suffering from severe hyperkalemia, you would expect
A) the membrane potential of nerves and muscles to be more negative.
B) the potassium ion concentration of the interstitial fluid to be less than normal.
C) muscle weakness and increased strength of twitch contractions.
D) abnormal cardiac rhythms.
E) All of the answers are correct.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
67) Draw a map that shows the renal compensation for acidosis. Draw another map for alkalosis.
68) Diagram the reactions and interactions of the renin-angiotensin system (RAS). Which condition is the primary stimulus for its activation?
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
69) Which leads to the lowest water loss during a day?
A) urine
B) feces
C) skin and lungs
D) metabolism
E) food and drink
70) The most potent stimulus for vasopressin release is
A) low potassium.
C) plasma osmolarity.
70)
B) blood volume.
D) blood pressure.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
71) The cellular mechanisms for renal handling of H+ and HCO3- involve several membrane transporters; name three.
72) What are the two mechanisms of bicarbonate reabsorption in the proximal tubule?
73) "Water, water, everywhere, nor any drop to drink" is a phrase from the Rime of the Ancient Mariner by Samuel Taylor Coleridge. This poem describes an ocean ship unable to sail to land and running out of its supply of fresh water; sailors have long known that drinking seawater cannot prevent death from dehydration. What would result if the sailors attempted to decrease their dehydration by drinking seawater? Defend your answer by describing kidney physiology. Why wouldn't reflexes, in response to dehydration, fully compensate? What does this show about the force allowing kidneys to retain water under more normal conditions?
74) What are oropharynx receptors, which hormone do they decrease, and how is it known that they exist? If a person stranded on a desert island drank seawater to try to quench his thirst, how would this affect the oropharynx receptors?
75) "Glucose, glucose, everywhere, nor any speck to utilize" is a phrase made up by one of the authors working on this test question. Similar to the irony of not being able to prevent dehydration by drinking seawater, people with untreated diabetes mellitus are unable to prevent starvation even though there is a large amount of glucose surrounding their cells; as if that is not bad enough, dehydration is also a problem. Explain why there is glucose in the urine of such people, why glucose is not present in the urine of normal people, and why diabetics become dehydrated.
76) Creating new food recipes is more successful when the chefs understand basic food chemistry. For example, to create a new cake recipe, one must understand the role of both acids and bases in leavening (rising, or trapping of tiny gas bubbles as dough is baking, to provide the characteristic texture). The principle is to add baking soda (NaHCO3) into an acidic batter, causing a chemical reaction resulting in gas production. Looking at the chemical formula, which gas do you think is formed? Summarize the chemical reaction that occurs in a cake batter that contains NaHCO3 and vinegar or acetic acid (produces acetate when ionized: CH3COO- + H+). What would happen to your cake if you didn't use enough baking soda? What would happen if you forgot to acidify your batter with vinegar or a similar food acid?
77) Gopal suffers from chronic emphysema. Blood tests show that his pH is normal but his bicarbonate levels are increased significantly. How can this be?
78) Chandi, a nursing student, has been caring for burn patients. She notices that they consistently show increased levels of potassium in their urine and wonders why. What would you tell her?
79) Mr. Gregory comes to the doctor with high blood pressure. Tests show that he also has increased levels of renin in his blood and atherosclerotic plaques that have nearly blocked blood flow through his renal arteries. Mr. Gregory does not understand. Explain to him how decreased blood flow in his renal arteries could cause renin secretion to increase. Map the pathways through which increased renin causes high blood pressure for Mr. Gregory.
80) How does decreased blood pressure affect the following: granular cells, glomerulus, cardiovascular control center, hypothalamus? Indicate if decreased blood pressure directly affects the organ or tissue above or acts through a reflex pathway. If it acts through a reflex pathway, name the reflex.
81) Layla, an undergraduate, has normal PCO2 levels, high H+ levels, low pH and bicarbonate levels. What type of disturbance is Layla suffering from and what might cause this? If her PCO2 were elevated, would your answer change? Explain.
82) Diabetes mellitus produces many homeostatic imbalances, including acidosis. The pH imbalance is due to ketoacidosis, which results from excessive accumulation of by-products of fat metabolism, as the body cannot meet energy needs from carbohydrate metabolism. Maria is a teenaged diabetic who sometimes does not taking her insulin. Her mother takes her to the hospital because her breathing has become deep and gasping. Explain Maria's breathing pattern. Which other compensatory responses may occur, and would they occur earlier or later than the respiratory response?
83) Diabetes mellitus produces many homeostatic imbalances, including acidosis. The pH imbalance is due to ketoacidosis, which results from excessive accumulation of by-products of fat metabolism, as the body cannot meet energy needs from carbohydrate metabolism. Maria is a teenaged diabetic who sometimes does not taking her insulin. Her body is beginning to develop ketoacidosis as a result. Create a chart to indicate and explain how her blood pH, HCO3, and PCO2 react, by indicating "increase," "decrease," or "no change."
1. ketoacidosis has just developed
2. respiratory compensation occurs
3. renal compensation occurs
84) The graph below had its labels removed. One axis is plasma osmolarity. The other axis is EITHER plasma vasop concentration OR plasma aldosterone concentration. Write the correct label on each axis of the graph, and explai you came to that conclusion.
Answer Key
Testname: UNTITLED39
1) E
2) A
3) A
4) A
5) B
6) E
7) B
8) B
9) B
10) C
11) B
12) A
13) A
14) B 15) C
16) A
17) D
18) D
19) A
20) B
21) E
22) B
23) A
24) C
25) A
26) C
27) B
28) B
29) D
30) E
31) E
32) C
33) D
34) B
35) D
36) C
37) B
38) B
39) E
40) B
41) A
42) A
43) B
44) B
45) D
46) D
47) B
48) A
49) A
50) D
51) C
52) D
53) A
54) D
55) B
56) Kidneys control urine concentration by varying the amounts of water and sodium reabsorbed in the distal nephron.
57) E
58) A
59) A
60) A
61) A
62) B
63) B
64) B
65) B
66) D
67) Figure 20.18 shows compensations for both acidosis and alkalosis.
68) Figure 20.10 diagrams these interactions. The primary stimulus is low blood pressure, detected in several ways.
69) B
70) C
71) Possible answers include:
1. apical Na+-H+ exchanger
2. basolateral Na+- HCO3- symport
3. H+- ATPase
4. H+- K+- ATPase
5. Na+- NH4+ antiporter
72) 1. convert HCO3- into carbon dioxide, then back into HCO32. through the metabolism of glutamine (see Fig. 20.17)
73) The osmolarity of seawater is higher than that of the kidney medulla, thus the osmotic gradient that normally allows net reabsorption of water does not exist. Seawater osmolarity is largely a result of permeant ions such as sodium and chloride, so ingested seawater raises plasma osmolarity when it is absorbed. When the kidneys form a filtrate of this high-osmolarity solution, the descending limb fails to reabsorb water because the kidney medulla has a lower osmolarity than the filtrate (opposite of normal), along its entire length, and in fact the medulla would lose water as it moved into the descending limb. While ions would be reabsorbed by the ascending limb as usual, it is not enough to drive sufficient water reabsorption. Reflexes such as secretion of water-preserving hormones are ineffective because, ultimately, water reabsorption depends only on osmosis, and the normal osmotic gradient has been disrupted.
74) Oropharynx receptors inhibit the sense of thirst when they come in contact with cool water. They also inhibit secretion of vasopressin (ADH). They have not been identified anatomically, but presence of even a small amount of cold water in the mouth and pharynx is known to satisfy thirst even if the water is not absorbed and thus does not actually alleviate dehydration. Presence of receptors that inhibit the thirst sensation are the best guess as to how this works. Presumably drinking seawater would temporarily reduce the sense of thirst by the same proposed mechanism.
75) Glucose is in the urine simply because the plasma concentration exceeds the number of glucose transporters in the kidney tubules, because plasma glucose is unusually high. Normal individuals are able to reabsorb all the glucose in the filtrate because plasma glucose concentrations are normally low (normal body cells absorb glucose, diabetic cells do not). Glucose in the filtrate raises the osmolarity of the filtrate, which decreases the relative osmotic gradient for reabsorption of water; thus more water is lost in the urine leading to dehydration.
76) CO2 gas is formed. NaHCO3 + CH3COO- + H+ → Na+ + CH3COO- + CO2 + H2O. Less gas would be produced, so the cake wouldn't rise normally. The chemical reaction would not occur, so the cake wo rise.
77) As long as the ratio of bicarbonate ion to carbonic acid is 20:1, the pH of body fluids will remain normal. Since Gopal's condition is chronic (long term) his body has compensated for the excess carbonic acid (the result of hypercapnea due to poor ventilation) by increasing the amount of bicarbonate to match the elevated level of acid. This process involves the kidneys where some of the excess carbon dioxide is converted into carbonic acid and the carbonic acid is allowed to dissociate. The hydrogen ions are secreted and the newly formed bicarbonate is conserved to maintain a proper buffering capacity.
78) When tissues are burned, cells are destroyed and the contents of their cytoplasm leak into the interstitial fluid and then move into the plasma. Since potassium ion is normally found within the cell, damage to a large number of cells would release relatively large amounts of potassium into the blood. The elevated potassium levels would stimulate the cells of the adrenal cortex that produce aldosterone. The elevated levels of aldosterone would promote sodium retention and potassium secretion by the kidneys, thus accounting for the elevated levels of potassium in the patient's urine.
79) Atherosclerotic plaques block blood flow, which decreases GFR and decreases pressure in the afferent arteriole. These are both stimuli for renin release. Renin secretion starts a cascade that produces angiotensin II, a vasoconstrictor. Vasoconstriction increases blood pressure, and the medullary control center responds to ANG II by also increasing ADH, aldosterone secretion, and thirst, collectively increasing blood pressure even further.
80) See Table 20.1 in the chapter.
81) Layla is likely suffering from metabolic acidosis, since his PCO2 is normal. If her PCO2 was elevated, then she would likely be suffering from respiratory acidosis. Metabolic acidosis may be caused by ingestion of methanol, aspirin, and ethylene glycol. Respiratory acidosis can be caused by drugs or alcohol depression, increased resistance in asthma, impaired gas exchange in fibrosis or severe pneumonia, and muscle weakness in muscular dystrophy and other muscle diseases. The most common cause is chronic obstructive pulmonary disease.
82) Maria's respiratory system is responding to her ketoacidosis. By hyperventilating, she removes more CO2 from her blood, which shifts the carbonic acid equation to the right, removing free H+ and raising pH. Chemical buffering in the blood occurs immediately after the initial pH disturbance, as this is an ongoing process. The kidneys buffer more slowly, so they are effective later.
83) 1. pH decreases by definition, HCO3- decreases as the carbonic acid reaction shifts to the right, PCO2 is unchanged because the excess is expelled by the lungs due to the higher gradient.
2. pH increases and HCO3- decreases as exhaled CO2 drives the carbonic acid reaction to the right, and PCO2 decrease as it is exhaled.
3. pH increases as H+ is excreted, HCO3- increases as it is reabsorbed, and PCO2 increases as respiration returns to normal.
84) The dependent variable is typically used for the y-axis, and the independent variable for the x-axis. Plasma osmolarity is the independent variable, and it regulates the secretion of hormones. As osmolarity increases, vasopressin secretion increases to promote water retention, but aldosterone secretion is inhibited to promote sodium loss. Therefore vasopressin concentration is the correct label for the y-axis. See Figure 20.6 in the chapter.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Digestion refers to the
A) input of food into the digestive tract.
B) release of substances into the lumen of the gut.
C) breakdown of food into particles small enough to cross epithelial cells.
D) absorption of nutrients in the gut.
E) progressive dehydration of indigestible residue.
2) Secretion refers to the
A) progressive dehydration of indigestible residue.
B) breakdown of food into particles small enough to cross epithelial cells.
C) release of substances into the lumen of the gut.
D) absorption of nutrients in the gut.
E) input of food into the digestive tract.
3) Which are most closely regulated by the body?
A) motility, secretion, and digestion
B) digestion and motility
C) secretion and digestion
D) absorption and motility
E) motility and secretion
4) Which is an accessory organ of digestion?
esophagus
colon
5) The is a significant site of absorption of water and electrolytes, but NOT of nutrients.
A) mouth
B) small intestine
C) stomach
D) large intestine
E) None of the answers are correct.
6) Which is the sequence of layers from the lumen to the outer wall of the digestive tract?
A) serosa, submucosa, mucosa, muscularis externa
B) submucosa, mucosa, serosa, muscularis externa
C) mucosa, submucosa, muscularis externa, serosa
D) submucosa, muscularis externa, serosa, mucosa
E) mucosa, submucosa, serosa, muscularis externa
7) The lamina propria and mucous epithelium are parts of the
A) serosa.
B) submucosa.
C) mucosa.
D) muscularis mucosa.
E) adventitia.
8) The layer of connective tissue between the digestive epithelium and a layer of smooth muscle is the
A) submucosa.
B) lamina propria.
C) myenteric plexus.
D) muscularis mucosae.
E) submucosal plexus.
9) Contraction of the alters the surface area by moving villi.
A) submucosal plexus
B) adventitia
C) submucosa
D) muscularis mucosae
E) mucosa
10) Rugae, plicae, and villi are all structures that
A) increase surface area.
B) secrete hormones.
C) provide mechanical digestion.
D) secrete enzymes.
E) provide immunity.
11) The motor activity of the muscularis externa is controlled by the
A) motilin.
B) extrinsic neurons.
C) submucosal plexus.
D) migrating motor complex.
E) myenteric plexus.
12) Intestinal crypts
A) only produce new cells for the mucosa of the small intestine.
B) only increase the surface area of the mucosa of the small intestine.
C) only function in the absorption of nutrients.
D) increase the surface area of the mucosa of the small intestine and produce new cells for the mucosa of the small intestine.
E) only carry products of digestion that will not pass through the walls of blood capillaries.
13) Chief cells secrete
A) mucus.
B) pepsinogen.
C) gastrin.
D) intrinsic factor.
E) hydrochloric acid.
14) G cells of the stomach secrete
A) pepsin.
B) enterokinase.
C) secretin.
D) cholecystokinin.
E) gastrin.
15) In the intestine, the epithelial cells have
A) electrical gap junctions. B) tight junctions. C) leaky junctions.
16) The subepithelial connective tissue of the GI tract, immediately beneath the epithelium, is the
A) muscularis mucosae.
B) submucosa.
C) submucosal plexus.
D) serosa.
E) lamina propria.
17) Between the layer of circular and longitudinal muscle in the muscularis externa is the
A) muscularis mucosa.
B) submucosa.
C) submucosal plexus.
D) mucosa.
E) myenteric plexus.
18) The myenteric plexus is
A) primarily composed of connective tissue.
B) a network of nerves.
C) a layer of longitudinal smooth muscle.
D) a layer of circular smooth muscle.
E) the mucus secreting layer of the digestive tract.
19) Peyer's patches are found in the
A) stomach.
B) pancreas.
C) esophagus.
D) intestine.
E) colon.
20) Features of the submucosa include
A) blood vessels, lymph vessels, and a major nerve network.
B) a major nerve network.
C) blood and lymph vessels.
D) Peyer's patches.
E) blood vessels, lymph vessels, a major nerve network, and Peyer's patches. 20)
21) The are sheets of peritoneal membrane that hold some of the intestines in their place.
A) adventitia
B) serosa
C) lamina propria
D) fibrosa
E) mesenteries
22) Slow waves are
A) segmental contractions.
B) reflexes that originate and are integrated in the enteric nervous system.
C) cycles of smooth muscle contraction and relaxation.
D) peristaltic contractions.
E) cycles of depolarization and repolarization.
23) are pacemakers for slow wave activity.
A) Interstitial cells of Cajal
B) G cells
C) Intrinsic neuron cells
D) Extrinsic neuron cells
E) Chief cells
24) Powerful contractions that occur a few times each day in the colon are called
A) mass movements.
B) tonic contractions.
C) segmentation.
D) phasic contractions.
E) peristalsis.
25) The swallowing center in the brain, which coordinates the muscular reflexes, is located in the
A) medulla oblongata.
B) hypothalamus.
C) pons.
D) cerebrum.
E) cerebellum.
26) Which does NOT occur when you swallow?
A) The lower esophageal sphincter relaxes. B) Respiration is inhibited.
C) The upper esophageal sphincter closes. D) The epiglottis closes.
27) Mucus functions in
A) lubrication only.
B) protection, lubrication, and enzyme activation.
C) protection only.
D) enzyme activation only.
E) protection and lubrication.
28) In the digestive system, HCl is released by , whereas HCO3- is secreted primarily from the .
A) the pancreas, parietal cells of the stomach
C) the liver, parietal cells of the stomach
29) Nutrient absorption occurs primarily in the
A) large intestine.
B) stomach.
C) liver.
D) small intestine.
B) parietal cells of the stomach, pancreas
D) parietal cells of the stomach, liver
E) stomach and small intestine. 29)
30) Amylases, the enzymes used to digest carbohydrates, are secreted by
A) the pancreas into the intestine only.
B) salivary glands into the mouth and the pancreas into the intestine.
C) salivary glands into the mouth and gastric glands into the stomach.
D) gastric glands into the stomach only.
E) salivary glands into the mouth only. 30)
31) Nearly 90% of our dietary calories from fat are in the form of
A) steroids.
B) triglycerides.
C) cholesterol.
D) fat-soluble vitamins.
E) phospholipids.
32) Bile is
A) made by the gallbladder only.
B) secreted by hepatocytes, made by the gallbladder, and released into the stomach.
C) released into the stomach only.
D) secreted by hepatocytes and made by the gallbladder.
E) secreted by hepatocytes only.
33) Functions of the large intestine include
A) absorption of most products of digestion.
B) temporary food storage.
C) absorption of water and production of feces.
D) chemical digestion of chyme.
E) All of these answers are correct.
34) The release of many GI tract hormones is stimulated by a particular food or substance. Which hormone is NOT paired with its stimulus?
A) CCK – fatty foods
B) GIP – glucose in the small intestine
C) gastrin – peptides and amino acids
D) motilin – acid in the stomach
E) secretin – acid in the small intestine
35) During the cephalic phase of gastric secretion,
A) production of gastric juice is inhibited.
B) there are increased action potentials along the vagus nerve to the stomach.
C) secretin inhibits parietal and chief cells.
D) the intestine reflexively inhibits gastric emptying.
E) the stomach responds to distention.
36) The gastric phase of gastric secretion is triggered by the
A) entry of food into the stomach.
B) entry of chyme into the large intestine.
C) entry of chyme into the small intestine.
D) release of cholecystokinin and secretin by the small intestine.
E) sight, thought, or smell of food.
37) An enzyme that will digest proteins into amino acids is
A) maltase.
B) amylase.
C) nuclease.
D) lipase.
E) carboxypeptidase.
38) Most products of fat digestion are absorbed by
A) lymphatic lacteals.
C) arterioles.
39) Which is true about GI muscle contractions?
B) capillaries.
D) veins.
A) Tonic contractions are sustained for minutes and occur in the small intestine.
B) Contractions of the smooth muscle do not depend on calcium.
C) Phasic contractions last only seconds and occur in the stomach and small intestine.
D) Cycles of smooth muscle contraction and relaxation are associated with fast wave potentials.
E) None of these statements are true.
40) Which statement is true?
A) Fructose moves across the apical membrane by active transport.
B) Glucose and galactose use different transporters in absorption.
C) Glucose and galactose absorption uses an apical Na+-glucose SGLT symporter.
D) A basolateral GLUT5 transporter moves glucose out of the intestinal epithelial cell.
E) None of the statements are true.
41) Bicarbonate secretion
A) neutralizes acid entering from the stomach into the duodenum and is secreted by apical Cl-HCO3- exchanger.
B) neutralizes acid entering from the stomach into the duodenum.
C) is not dependent on high levels of carbonic anhydrase to maintain bicarbonate production.
D) is secreted by apical Cl-HCO3- exchanger.
E) is secreted by the acinar cells.
42) Saliva secretion is primarily a result of
A) increased sympathetic stimulation.
B) increased somatic motor stimulation.
C) increased parasympathetic stimulation.
D) decreased somatic motor stimulation.
E) decreased parasympathetic stimulation.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the following structures with the appropriate description
43) location of most peptic ulcers
44) section where chyme is processed to remove water and electrolytes, leaving waste products of digestion
45) located at the ventral end of the cecum
46) distal-most section of small intestine
Match the following structures with their functions.
47) chyme is released from here
48) organ that adds secretions to the duodenum through a duct
49) location of a smooth muscle band that prevents premature emptying of the stomach
50) organ where most digestion occurs
Match the structure to its function.
51) Carbohydrate digestion begins here.
52) Carbohydrate digestion by human enzymes is completed here.
53) Protein digestion begins here.
54) Protein digestion is completed here.
55) Fat digestion begins here.
56) Fat digestion by human enzymes is completed here.
Match each product with the cell or region that secretes or contains it.
57) parietal cells
58) goblet cells
59) brush border
60) pancreatic cells
pylorus
small intestine
stomach
enzymes
more than one of these
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
61) The largest collection of tissue in the body is the gut-associated lymphoid tissue (GALT).
lymphoid B) nervous C) epithelial D) muscle
62) Digestion is almost completely finished in the A) small intestine. B) large intestine. C) stomach. D) anus.
63) The three sections of the small intestine, in order according to movement of its contents, are
A) jejunum, ileum, colon.
C) jejunum colon, ileum.
B) duodenum, ileum, jejunum.
D) duodenum, jejunum, ileum.
64) Most absorbed nutrients first enter the blood of the system.
A) lymphatic B) immune
C) hepatic portal D) arterial
65) The primary complex carbohydrate ingested and digested by people is A) starch. B) cellulose. C) fiber. D) glycogen. E) glucagon.
66) After processing in the stomach, the gastric contents are referred to as A) food. B) chyme. C) feces. D) filtrate.
67) Bile salts aid in the digestion of fats by large fat droplets.
A) generating B) digesting fats within C) emulsifying
D) absorbing
68) is intestinal gas produced by bacteria in the colon during the metabolism of indigestible carbohydrates.
A) Defecation
B) Haustra
C) Flatus
64)
65)
66)
67)
68)
D) Tenia Coli
69) The enzyme that digests starch into disaccharides is A) maltase. B) sucrose. C) amylase. D) lactase.
70) Maltose is broken down by maltase into two molecules of A) glucose. B) galactose. C) amylase. D) starch.
71) are tiny droplets of fatty acids, cholesterol, phospholipids, mono- and diglycerides, and bile salts.
A) Micelles
C) Enterocyte membranes
69)
70)
71)
B) Lacteals
D) Chylomicrons
72) Slow waves originate in modified smooth muscle cells called A) mucous cells. B) goblet cells. C) smooth muscle sphincters. D) interstitial cells of Cajal.
73) The is a "housekeeping function" that sweeps food remnants and bacteria out of the upper GI tract and into the large intestine.
A) slow wave
72)
73)
B) segmental contraction
C) migrating motor complex D) peristaltic contraction
74) involve short segments of intestine that alternately contract and relax. They are responsible for
A) Peristaltic contractions, mixing B) Segmental contractions, mixing C) Segmental contractions, pushing a bolus forward D) Peristaltic contractions, pushing a bolus forward
74)
75) The exocrine portion of the pancreas consists of lobules called , which secrete .
A) islets, hormones
C) acini, digestive enzymes
B) islets, digestive enzymes
D) acini, hormones
76) digest terminal peptide bonds to release amino acids.
A) Proteases
C) Endopeptidases
77) Bile is secreted from the and stored in the
A) liver, gallbladder
C) pancreas, hepatocytes
B) Lipases
D) Exopeptidases
B) hepatocytes, pancreas
D) gallbladder, liver
78) Digestive reflexes integrated in the CNS are called reflexes.
A) long B) deglutition C) short D) defecation
79) Long reflexes that originate outside the digestive system include reflexes and reflexes, which are called reflexes.
A) feedforward, emotional, short
B) submucosal plexus, myenteric plexus, short
C) submucosal plexus, myenteric plexus, cephalic
D) feedforward, emotional, cephalic
80) Short reflexes of the digestive system are integrated in the nervous system.
A) parasympathetic
C) central
B) enteric
D) peripheral 80)
81) The primary products of protein digestion are , , and .
A) polysaccharides, disaccharides, monosaccharides
B) nucleic acid polymers, DNA, RNA
C) free amino acids, dipeptides, tripeptides
D) triglycerides, fatty acids, glycerol 81)
82) Enzymatic digestion of fats involves , which breaks down
A) bile, cholesterol
C) lipase, triglycerides
82)
B) pepsin, proteins
D) amylase, carbohydrates
83) is a protein cofactor secreted by the pancreas that allows lipases access to fats inside the bile salt coating.
A) Lipase B) Phospholipase C) Colipase D) Monoglyceride
83)
84)Vitamin intestine. must be complexed with a protein called to be absorbed from the small 84)
A) K, hydrogen sulfide
C) A, Olestra
B) B12, intrinsic factor
D) D, somatomedins
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
85) Defects in which channel lead to the disease cystic fibrosis? Which ion does this channel transport?
86) What is the ENS, and when was it discovered? What is its significance, what is its nickname, and what are the characteristics that justify that nickname?
87) Where are long reflexes and short reflexes integrated?
88) In one sentence, briefly summarize the generalized function of regulatory peptides secreted by the GI tract. Then, list the key GI hormones, spelling them out and also writing their abbreviations where appropriate.
89) List the six types of epithelial cells associated with gastric glands and the secretions from each.
90) Name two functions of cholecystokinin (CCK).
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
91) Put the following steps of fat digestion and absorption in order:
1. Bile salts coat fat droplets.
2. Cholesterol is transported into cells.
3. Chylomicrons are formed.
4. Chylomicrons are removed by lymphatic system.
5. Monoglycerides and fatty acids move out of micelles.
6. Pancreatic lipase and colipase break down fats.
A) 2, 6, 5, 1, 3, 4
B) 1, 6, 5, 2, 3, 4
C) 1, 2, 3, 4, 6, 5
D) 6, 3, 4, 1, 2, 5
E) None of the answers are correct. 91)
92) During defecation,
A) the external anal sphincter contracts.
B) the internal anal sphincter contracts.
C) distension in the rectal wall activates a spinal reflex.
D) the internal anal sphincter is consciously relaxed.
E) distension in the rectal wall activates a short reflex. 92)
93) Decreased levels of bile salts in the bile would interfere with digestion of
A) protein.
B) nucleic acids.
C) fat.
D) carbohydrates.
E) vitamins and minerals.
94) In response to the acid in the duodenum, the blood levels of
A) gastrin increase.
B) secretin increase.
C) cholecystokinin decrease.
D) enterocrinin decrease.
E) All of these answers are correct. 94)
95) A blockage of the ducts from the parotid glands would
A) result in the production of less viscous saliva.
B) decrease carbohydrate digestion in the mouth.
C) decrease the lubricating properties of saliva.
D) decrease the sense of taste.
E) cause all of these effects.
96) In response to the hormone secretin, the pancreas secretes a fluid that contains
A) only amylase.
B) bile.
C) only proteases.
D) bicarbonate.
E) enzymes.
97) In response to the hormone cholecystokinin (CCK), the pancreas secretes a fluid that contains
A) only proteases.
B) bicarbonate.
C) only amylase.
D) bile.
E) enzymes.
98) Digestion of an unlabeled carbohydrate results in increased amounts of the monosaccharides glucose and galactose. Which is most likely to be the original, unlabeled carbohydrate?
A) sucrose B) glycogen C) maltose D) lactose E) cellulose
99) Diarrhea often results from intestinal infections. Why?
A) Dehydration of the body will kill the bacteria causing the infection.
B) Loss of electrolytes will kill bacteria.
C) Bacterial toxins enhance the secretion of Cl- and water.
D) The immune system increases the production of enzymes for added protection.
100) A drug that blocks the action of carbonic anhydrase in parietal cells would result in
A) increased protein digestion in the stomach.
B) decreased production of pepsinogen by chief cells.
C) decreased gastrin production.
D) a lower pH during gastric digestion.
E) a higher pH during gastric digestion.
101) A drug that blocks the action of the hormone cholecystokinin would affect
A) the amount of bile produced by the liver.
B) the level of intestinal gastrin.
C) pancreatic secretions.
D) secretions of the duodenal glands.
E) All of the answers are correct. 101)
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the hormone with the correct statement.
102) secreted by cells in the stomach
103) inhibits gastric emptying
104) stimulates bile release
105) stimulates insulin release
106) smooth muscle of intestines is a target
Match the structure or compound to its function.
107) apical transporter for iron absorption
108) basolateral transporter for ionized iron
109) hormone that decreases iron absorption
110) blocks cholesterol absorption
A) gastrin
B) motilin
C) gastric inhibitory peptide
D) secretin
E) cholecystokinin
111) transporter for cholesterol absorption A) ezetimibe B) DMT1 C) hepcidin D) NPC1L1 E) ferroportin
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
112) Where does carbohydrate digestion begin? Which enzyme is involved, and which reaction does it catalyze?
113) The mucosa of the majority of the digestive tract contains simple columnar epithelium, while the esophagus and the anus have stratified squamous epithelium. Why is this the case? What purpose does each type of epithelium serve in the digestive tract?
114) List the key components of bile. Is bile action similar to the action of lipases? Explain.
115) List the four basic processes of the digestive system, and define each.
116) Proteins must first be enzymatically degraded to single amino acids before entering the capillaries of the hepatic portal system. Is this true or false? What is the significance of this? Is absorption of carbohydrates and lipids restricted to monomers? Explain.
117) Draw a cell that secretes bicarbonate into the lumen of the pancreas, selecting transporters and/or enzymes from following list (you may or may not need them all):
chloride channel
CFTR channel
GLUT4
H+-K+-ATPase
Na+-Cl-K+ Symport
Cl- HCO3- Antiport
Cl- HCO3- Symport
carbonic anhydrase
K+ leak channel
leaky junctions
Na+-K+-ATPase
Na+-H+ antiport
Label the cell showing the lumen, interstitial fluid, the basolateral membrane, and the apical membrane.
118) Compare and contrast gastrin, CCK, secretin, GIP, motilin, and glucagon-like peptide 1. In your answer, include the following details for each term: secreted by, target(s), effects, and stimulus for release.
119) Draw a map of a short reflex that might occur in response to ingestion of food. Include on your map the stimuli, afferent sensors, integrating centers, efferent pathways, targets, and tissue responses.
120) Diagram intestinal absorption of peptides. Begin with the arrival of a protein in the lumen of the small intestine, and continue the diagram until the absorbed peptides reach the hepatic portal vein. Include in your diagram the enzymes and transporters that might be involved; and label the intestinal lumen, the apical and basolateral membranes the peptides might cross, and the anatomical pathway the absorbed peptides would take to reach the hepatic portal vein.
121) Make a map showing the relationships of the following terms involved with gastric secretion.
chief cell
D cell
ECL cell
enteric sensory neuron
G Cell gastrin
H+ histamine parietal cell
pepsin
pepsinogen somatostatin vagus nerve
Where appropriate, indicate stimulatory or inhibitory effect. Terms may be added as needed.
122) Name the proenzymes secreted by the pancreas. Which one is involved in the activation of the other proenzymes? What are their active forms?
123) The enteric nervous system and the CNS have several similarities. What are they?
124) Draw a cell that secretes HCl into the lumen of the stomach, selecting transporters and/or enzymes from the follo list (you may or may not need them all):
chloride channel
CFTR channel
GLUT4
carbonic anhydrase
H+-K+-ATPase
Cl- HCO3- Antiport
Cl- HCO3- Symport
Na+-K+-ATPase
Label the cell showing the lumen, interstitial fluid, the basolateral membrane, and the apical membrane.
125) One way to determine the total energy in calories of a food is to burn it in a device called a bomb calorimeter. The heat produced during combustion minus the heat added to begin the combustion is the total calories in the food. The typical human digestive tract does not absorb all of the calories in food; thus it is not 100% efficient. Also, calories in indigestible organic compounds may not be absorbed at all, and thus can be considered to be "z calorie" relative to human nutrition. Artificial sweeteners and fats are designed to produce desired sensation in t mouth without being absorbed. These are organic compounds that would release heat in a bomb calorimeter, thu technically have calories.
A. What does this suggest about the accuracy of the bomb calorimeter in determining available food calories for humans? What would be the results of bomb calorimetry of human feces?
B. What is it about a particular food substance that may prevent absorption of its calories?
C. What happens to the "zero-calorie" molecules as they pass through the digestive tract? What are the potential effects on defecation?
126) Cody has always carefully controlled her caloric intake, and is lean. During her pregnancy, she continued to eat the same, hoping that taking prenatal vitamins and minerals would help her fetus would grow normally. Her only complication during pregnancy was persistent constipation and hemorrhoids. She gained only the minimum weight suggested by her doctor, and delivered a healthy, full-term infant. She quickly returned to her pre-pregnancy weight. Propose an explanation for how she managed to gain enough weight, did not violate the law of conservation of mass, and for her only complication. What does this suggest about "eating for two" that some pregnant women do?
127) A condition known as lactose intolerance is characterized by painful abdominal cramping, gas, and diarrhea. The cause of the problem is an inability to digest the milk sugar, lactose. How would this cause the observed symptoms?
128) Muna came down with the flu. She experienced severe vomiting or mostly stomach contents, for three days, and now is having chest pains. She is calling one of her symptoms "heartburn," but reported that it felt as if she had swallowed a small apple. Certain that she was having a heart attack, Muna rushed to the emergency department. The doctor took her history and symptoms, and reassured her that she only had esophagitis. How did the physician conclude this? Is her blood pH higher or lower than normal?
129) In some severe cases, a person suffering from stomach ulcers may have surgery to cut the branches of the vagus nerve that innervates the stomach. How would this help the problem?
130) Essential nutrients are those that our cells require but cannot make, and thus they must be present in the diet. Only some amino acids and some fatty acids are essential. What does that suggest about extreme diets that eliminate fats or proteins? What does that suggest about our carbohydrate intake? Describe the typical American diet, in terms of relative amounts of ingested carbohydrates, fats, proteins, and nucleic acids. Propose some explanations for why one of those is predominant.
131) What would be the nutritional consequence of excessive antacid use?
132) You and your lab partners in a human anatomy course removed the intestines from an adult cadaver, and cut away connective tissues as necessary to uncoil the intestines into a straight line that could be measured. Your professor told you that the intestinal tract of an adult of this size and gender is typically about 13 ft. Your measurement is 22 ft. One of the lab partners insists that everything is smaller in preserved cadavers due to dehydration. Address this suggestion, and propose some other explanations for the difference.
133) You are studying the toxic effects of a newly-discovered tropical plant extract. From preliminary studies, it appears that the toxin prevents H+-dependent membrane transport. Explain which digestive processes may be impaired.
134) Cholesterol is absorbed without being digested into smaller pieces. How does this compare to absorption of carbohydrates and proteins? Which characteristic of cholesterol suggests it would be transported by simple diffusion? What is the evidence that transport proteins are involved in cholesterol absorption? Does this discovery rule out transport by simple diffusion? Explain.
135) Chronic inflammation of the pancreas, or pancreatitis, impairs the digestive functions of this organ. What would be the effect on digestion and absorption of carbohydrates, fats, and proteins if acinar cells are impaired? What if duct cells are impaired? Which hormones may be used to treat pancreatitis?
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
136) In the body, 80% of all lymphocytes, a type of immune system cell, are thought to be present in the A) mouth.
B) large intestine. C) stomach.
D) small intestine. E) appendix.
137) Feedforward reflexes are also reflexes.
A) cephalic B) short C) emotional D) medium
138) A possible treatment for Salmonella could involve
A) activating cytokine receptors. B) increasing macrophages. C) increasing lymphocytes. D) blocking M cell receptors.
139) Vomiting and diarrhea are similar since both
A) are used to prepare patients for surgery. B) work to rid the body of damaging agents. C) are stimulated by the CNS.
D) use normal GI motility to move substances.
Answer Key
Testname: UNTITLED40
1) C
2) C
3) E
4) C
5) D
6) C
7) C
8) B
9) D
10) A
11) E
12) D
13) B
14) E 15) C
16) E
17) E
18) B
19) D
20) A
21) E
22) E
23) A
24) A
25) A
26) C
27) E
28) B
29) D
30) B
31) B
32) E
33) C
34) D
35) B
36) A
37) E
38) A
39) C
40) C
41) A
42) C
43) A
44) B
45) D
46) C
47) C
48) D
49) A
50) B
Answer Key
Testname: UNTITLED40
51) C
52) B
53) A
54) B
55) A
56) B
57) C
58) D
59) A
60) B
61) A
62) A
63) D
64) C
65) A
66) B
67) C
68) C
69) C
70) A
71) A
72) D
73) C
74) B
75) C
76) D
77) A
78) A
79) D
80) B
81) C
82) C
83) C
84) B
85) cystic fibrosis transmembrane regulator (or CFTR chloride channel); it transports chloride.
86) ENS is the enteric nervous system, discovered over 100 years ago. The ENS controls reflexive peristalsis in the intestine, independent of the CNS. The ENS is nicknamed the "little brain" because it shares these characteristics with the actual brain: secretion of neurotransmitters and neuromodulators, and the presence of glial cells, a diffusion barrier, and integrating centers.
87) Short reflexes are integrated within the enteric nervous system without outside input, and long reflexes are integrated in the central nervous system.
88) Generally, GI peptides stimulate or inhibit motility and secretion. The key hormones secreted by the GI tract are: gastrin, cholecystokinin (CCK), secretin, gastric inhibitory peptide (GIP), motilin, and glucagon-like peptide-1 (GLP-1).
89) Parietal cells secrete HCl and intrinsic factor; chief cells secrete pepsinogen and gastric lipase; D cells secrete somatostatin; ECL cells secrete histamine; G cells secrete gastrin; mucous cells secrete mucus and bicarbonate.
90) Enhances satiety, stimulates gallbladder contraction and pancreatic enzyme secretion, and inhibits gastric emptying and acid secretion. See Table 21.1 in the chapter.
91) B
92) C
93) C
94) B
95) B
96) D
97) E
98) D
99) C
100) E
101) C
102) A
103) D
104) E
105) C
106) B
107) B
108) E
109) C
110) A
111) D
112) Salivary amylase is secreted into the mouth and digests large glucose polymers, like starch, into smaller glucose chains and the disaccharide maltose.
113) Columnar epithelium is primarily responsible for secreting and absorbing materials across its membranes whereas stratified squamous epithelium is primarily present for protection of the tissues beneath it. The stomach and intestines secrete enzymes and other chemicals important for digestion, and the intestines are the primary sites where the body absorbs nutrients and water, so it makes sense for these locations to have simple columnar epithelium. The esophagus carries undigested food from the mouth to the stomach, not absorbing anything, so it makes sense that it would have stratified squamous epithelium to protect the tissues beneath it from the ingested food particles. The anus is primarily a passageway for feces to leave the body, and it would not be beneficial for the feces to come into contact with the tissue beneath it, so stratified squamous epithelium also makes sense in the anus.
114) Bile salts, bile pigments, and cholesterol are the key components of bile. Bile does not contain enzymes, and unlike lipases, bile has no enzymatic action of its own; rather, bile emulsifies lipids so that lipases (with the help of colipase) have sufficient access to their lipid substrates.
115) 1. Digestion is the chemical and mechanical breakdown of foods into smaller units.
2. Absorption is the active or passive transfer of substances from the lumen of the GI tract to the extracellular fluid.
3. Motility is the movement of material in the GI tract as a result of muscle contraction.
4. Secretion refers to both transepithelial transfer of water and ions from the ECF to digestive tract lumen and also the re of substances synthesized by GI epithelial cells.
116) False. Absorption of small peptides allows peptides to cause food allergies. The transporters for peptides are also responsible for absorption of some drugs. Carbohydrates are digested to monosaccharides because there are no transporters for larger carbohydrates. Lipids are absorbed as cholesterol, fatty acids, and monoglycerides, primarily by simple diffusion because they are lipophilic.
117) See Figure 21.14 in the chapter.
118) See Table 21.1 in the chapter.
119) Maps will vary. See Figure 21.5 in the chapter.
120) See Figures 21.12 and 21.18 in the chapter.
121) Maps will vary. Figure 21.9 and 21.10 in the chapter.
122) Proenzymes include: trypsinogen, chymotrypsinogen, procarboxypeptidase, procolipase, and prophospholipase. When it comes into contact with enteropeptidase in the brush border of the intestine, trypsinogen is converted to trypsin, which then activates the other proenzymes. The pathway can be found in Figure 21.14 in the chapter.
123) See "The Enteric Nervous System Can Act Independently" section of the chapter.
124) See Figure 21.9 in the chapter.
125) A. Bomb calorimetry is not 100% accurate because it does not take into account that some calories are not absorbed. Hu feces would be determined to contain some calories.
B. In order for nutrients in a food to be usable by the body, they must be chemically digested and absorbed. Digestive e exhibit specificity, so they do not digest molecules that are different in structure from their substrate. If an artificial food is indigestible, this simply means that the body lacks the appropriate enzyme to digest it and/or lacks a membrane trans to absorb it.
C. Gut bacteria may be able to digest and absorb these compounds. Extra organic solute present in the gut may cause re of water and production of bacterial gas as the bacteria digest the substance in question. This can lead to distention, discomfort, and diarrhea.
126) She must have inefficiently absorbed calories prior to her pregnancy, losing many potential calories in her feces. When she became pregnant, one of her physiological changes included an increase in nutrient (and thus calorie) absorption. This would also contribute to her constipation, as her feces retained less water than normal and thus were more difficult to eliminate. It is not possible for her to have gained more weight than she ate; no one can violate the law of conservation of mass. Most obstetricians recommend only a slight increase in calories during pregnancy for this reason, and women who indulge in overeating too often are likely to gain unnecessary body fat and may produce a fetus that is larger than it should be.
127) If an individual cannot digest lactose, then the sugar will pass through to the large intestine in an undigested form. The presence of the extra sugar in the chyme increases the osmolarity of the chyme, resulting in less water being reabsorbed by the intestinal mucosa. The bacteria that inhabit the large intestine can metabolize the lactose, and in the process they produce large amounts of carbon dioxide. The gas overstretches the intestine, which stimulates local reflexes that increase peristalsis. The combination of more fluid contents and increased peristalsis produces the symptom of diarrhea. The overexpansion of the intestine by gas causes the severe pain and abdominal cramping, and of course, the increase in intestinal gas release is directly related to increased gas production by the bacteria.
128) Acid reflux irritated the esophageal lining, causing it to swell. Her pH is higher than normal due to loss of H+ from her stomach.
129) The vagus nerve carries neurons of the parasympathetic nervous system. These neurons control gastric secretions, notably the secretion of acid and enzymes. Severing these branches would eliminate neural stimulation from the central nervous system, thus eliminating the release of gastric fluids in response to anxiety and other higher-order stimuli when there is no food in the stomach. Normal digestive function would still occur, governed by various hormones and intramural neural reflexes.
130) Complete elimination of proteins or fats would eventually be fatal. Carbohydrates need not be consumed at all, from the standpoint of essential nutrients. In reality, however, a carbohydrate-free diet would cause metabolic problems because of consequences of manufacturing glucose from lipids and proteins, as described in Chapter 22 in the text. About half of the typical dietary intake is carbohydrate, with most of the remainder in the form of fats and proteins. Carbohydrates are the primary molecule in plant products, which makes up most of what we eat because of abundance and price.
131) Antacids make the stomach pH higher than normal, which will interfere with protein digestion because the enzymes would not be as efficient.
132) There is no doubt of some individual variation, so the measurement is expected to be at least a little different. Most of the difference is due to loss of living muscle tone, which normally keeps the tract contracted. While it is true that preserved tissues may shrink from dehydration, this is more than compensated by the loss of muscle tone.
133) Absorption of some amino acids, dipeptides, and tripeptides may be impaired, as well as iron and sodium absorption, because these are dependent upon an H+ exchanger or cotransporter. HCl secretion into the stomach, which acidifies the lumen for protein digestion, may also be impaired.
134) Carbohydrates are digested to monosaccharides before they are absorbed. Proteins are absorbed as amino acids, di- or tripeptides, or even oligopeptides. As a lipid, cholesterol can dissolve in the phospholipid bilayer and therefore cross membranes by simple diffusion. The drug ezetimibe inhibits cholesterol absorption, suggesting there must be a membrane transporter. This discovery does not rule out additional transport of cholesterol by simple diffusion, but does suggest there is a significant amount of transport dependent upon a transport molecule.
135) Acinar cells secrete digestive enzymes for all three classes of molecules, therefore, nutrient digestion and consequent absorption would be decreased. Duct cells secrete bicarbonate, which counteracts the acidic nature of the chyme entering from the stomach and allows the pancreatic enzymes to function. The loss of these cells would also decrease digestion and absorption of the three classes of nutrient. Cholecystokinin stimulates pancreatic enzyme secretion and secretin stimulates bicarbonate secretion.
136) D 137) A 138) D
139) B
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Adipocytes secrete the hormone
A) leptin.
B) insulin.
C) neuropeptide Y.
D) ghrelin.
E) orexin.
2) Most obese humans are deficient in leptin.
A) True
B) False
3) The brain neurotransmitter that is the stimulus for food intake is
A) orexin.
B) ghrelin.
C) neuropeptide Y.
D) leptin.
E) insulin.
4) Energy input equals energy output. This statement reflects the
A) second law of thermodynamics.
B) first law of thermodynamics.
C) law of mass balance.
5) The first law of thermodynamics states that
A) natural processes move from order to disorder, or entropy.
B) the total amount of energy in the universe is constant.
C) energy can be created or destroyed.
D) what heats up must cool down.
E) there is no way a process can increase the amount of order.
6) One kilocalorie (kcal) is the amount of energy needed to raise 1 of water by one degree Celsius.
A) tablespoon
B) gallon
C) cup
D) milliliter
E) liter
7) A bomb calorimeter measures
A) the carbon dioxide produced when a food sample is completely combusted.
B) both carbon dioxide produced and oxygen consumed when a food sample is completely combusted.
C) the heat released when a food sample is burned.
D) only the food calories available to the human body.
E) the oxygen consumed when a food sample is completely combusted.
8) Which can be measured to determine a person's metabolic rate?
A) only oxygen consumed by body
B) only carbon dioxide produced by body
C) only heat released from body
D) heat released from body, oxygen consumed by body, and carbon dioxide produced by body
E) None of these answers are correct.
9) The respiratory quotient is for consumed carbohydrates compared to proteins and fats. A) lowest B) the same C) highest
10) The most practical way to estimate a person's basal metabolic rate is to measure it when the person is
A) resting after a 12-hour fast.
B) sleeping.
C) resting after a large meal.
11) Metabolism is a term that describes
A) only chemical reactions that release ATP from living cells.
B) all work done by a living organism.
C) the energy released from chemical bonds in living cells.
D) all chemical reactions that take place within an organism.
E) the extraction of nutrients from biomolecules.
12) Anabolic pathways include
A) reactions that release energy and reactions that result in the synthesis of large biomolecules.
B) reactions that require a net input of energy.
C) reactions that release energy.
D) reactions that result in the synthesis of large biomolecules.
E) reactions that require a net input of energy and reactions that result in the synthesis of large biomolecules.
13) The brain relies solely on as its energy source. If it is deprived of this substrate, the cells soon die.
A) glucose B) amino acids C) fatty acids D) insulin
14) Gluconeogenesis refers to
A) converting glucose to glycogen storage.
B) removing fatty acids from adipose storage.
C) creating glucose from non-carbohydrate precursors.
D) converting glucose to storage as adipose tissue.
E) removing glucose from storage as glycogen.
15) An enzyme that digests fats is
A) kinase. B) hydrolase. C) lipase. D) ligase. E) lyase.
16) The liver and skeletal muscles store glucose as for a ready energy source.
A) glycogen
B) glucose
C) urea
D) ketone bodies
E) lipids
17) Which is NOT produced in the body for the purpose of storing extra calories?
A) protein
B) carbohydrate
C) fat
D) All of these are produced in the body for that purpose.
18) The nutrients that yield the most energy per gram when metabolized are
A) fats.
B) carbohydrates.
C) nucleic acids.
D) proteins.
E) vitamins.
19) Diet-induced thermogenesis is highest after ingestion of
A) proteins.
C) fats.
B) carbohydrates.
D) spicy foods, like jalapeno peppers. 19)
20) The synthesis of glucose from a noncarbohydrate precursor is referred to as
A) gluconeogenesis.
B) glycogen.
C) glycogenolysis.
D) glycolysis.
E) glycogenesis.
21) During the fasting state, the energy stores of the become the major source of glucose for the whole body.
A) brain
B) muscles
C) liver
D) adipose tissues
E) pancreas
22) Lipoproteins that carry mostly cholesterol and phospholipids out of the plasma to the liver are called
A) very low-density lipoproteins (VLDLs).
B) low-density lipoproteins (LDLs).
C) very high-density lipoproteins (VHDLs).
D) high-density lipoproteins (HDLs).
E) intermediate-density lipoproteins (IDLs).
23) Before converting amino acids into intermediates for energy metabolism, they must first undergo
A) delousing.
B) denaturation.
C) depeptidization.
D) deamination.
E) detoxification.
24) When amino acids are metabolized for energy, the nitrogen is converted to urea and then is excreted from the body by the
A) sweat glands.
B) spleen.
C) skin.
D) kidneys.
E) liver.
25) The reactions where fats are broken down into glycerol and fatty acids are called
A) gluconeogenesis.
B) glycolysis.
C) lipolysis.
D) glycerolysis.
E) liposuction.
26) The process of disassembling fatty acids into two-carbon units inside mitochondria is called
A) deamination.
B) ketonization.
C) beta-oxidation.
D) oxidative phosphorylation.
E) chemiosmosis.
27) A substance that the liver produces when metabolizing fatty acids that is both an energy source and a potentially-harmful substance is
A) beta units.
B) ammonia.
C) rancid fatty acids.
D) urea.
E) ketone bodies.
28) The alpha cells of the pancreas secrete
A) digestive enzymes.
B) cortisol.
C) glucagon.
D) renin.
E) insulin. 28)
29) The beta cells of the pancreas produce
A) insulin.
B) renin.
C) digestive enzymes.
D) cortisol.
E) glucagon.
30) D cells in the islet of Langerhans secrete
A) amylin.
B) glucagon.
C) pancreatic polypeptide.
D) somatostatin.
E) insulin.
31) When blood glucose levels increase, as in the "fed" state,
A) only peripheral cells take up less glucose.
B) only insulin is secreted.
C) only protein synthesis decreases.
D) only glucagon is secreted.
E) All of these answers are correct.
32) When blood glucose levels decrease, as in the "fasted" state, only
A) protein synthesis decreases.
B) peripheral cells take up less glucose.
C) insulin is secreted.
D) glucagon is secreted.
E) All of these answers are correct.
33) The feeding and satiety centers are located in the
A) cerebrum.
B) cerebellum.
C) medulla oblongata.
D) pons.
E) hypothalamus.
34) During the absorptive state,
A) the liver synthesizes glycogen.
B) adipocytes release fatty acids to the circulation.
C) glucagon levels are increased.
D) skeletal muscles break down glycogen.
E) All of these answers are correct.
35) During starvation,
A) structural proteins cannot be used as a potential energy source.
B) gluconeogenesis increases.
C) circulating ketone bodies decrease.
D) carbohydrate utilization increases.
E) All of these answers are correct.
36) The brain can use for energy.
A) only fats
B) only glucose
C) only ketones
D) only lactate
E) both glucose and ketones
37) Which factors increase basal metabolic rate?
A) acetylcholine
B) thyroid hormones and epinephrine
C) epinephrine
D) insulin
E) thyroid hormones
38) Insulin secretion
A) is inhibited by GLP-1.
B) is stimulated by parasympathetic neurons.
C) decreases in response to increased amino acid concentrations.
D) is stimulated by sympathetic neurons.
E) None of these answers are correct.
39) A primary target tissue for insulin is the
A) intestine.
B) liver.
C) brain.
D) brain and liver.
E) brain, liver, and intestine.
40) GLUT4 transporters are
A) stored in cytoplasmic vesicles and found in adipose and skeletal muscles.
B) stored in cytoplasmic vesicles.
C) found in adipose and skeletal muscles.
D) inserted into the plasma membrane by endocytosis.
E) inserted into the plasma membrane in response to glucagon.
41) Insulin
A) only stimulates glycolysis.
B) stimulates glycolysis and inhibits gluconeogenesis.
C) only stimulates lipolysis.
D) stimulates glycolysis and lipolysis.
E) only inhibits gluconeogenesis.
42) Glucagon
A) stimulates gluconeogenesis and primarily targets the liver.
B) stimulates gluconeogenesis.
C) primarily targets the liver.
D) stimulates gluconeogenesis and primarily targets skeletal muscle.
E) primarily targets skeletal muscle.
43) Dehydration can result from
A) heat exhaustion and diabetes.
B) diabetes.
C) gluconeogenesis.
D) heat exhaustion.
E) CCK. 43)
44) Amylin
A) helps regulate glucose homeostasis by speeding up gastric emptying.
B) is co-secreted with insulin.
C) is co-secreted with glucagon.
D) is co-secreted with insulin and helps regulate glucose homeostasis by speeding up gastric emptying.
E) is co-secreted with glucagon and helps regulate glucose homeostasis by speeding up gastric emptying.
45) In type I diabetes, a hyperglycemic hyperosmolar state may occur. Which best describes this state?
A) Blood osmolarity is below normal levels due to elevated glucose.
B) Plasma glucose and blood osmolarity levels are above normal.
C) There is decreased water intake.
D) There are low levels of vasopressin (ADH).
E) ATP production is increased due to the increased levels of glucose in cells.
46) Homeothermic refers to
A) regulating body temperature within a narrow range.
B) natural treatments or remedies.
C) shivering.
D) warm relationships with others of the same gender.
47) Convective heat loss occurs when
A) a cooler object rests on the body's surface.
B) one swims in water below body temperature.
C) warm air rises from the body's surface.
D) water evaporates from the skin's surface.
E) All of the answers are correct.
48) Nearly half of heat is lost from the body through the process of
A) conductive heat loss.
B) convective heat loss
C) evaporative heat loss.
D) radiant heat loss.
E) concentrative heat loss. 48)
49) Specific responses to changes in body temperature are regulated by the
A) hypothalamus.
B) cardiac output.
C) thermoreceptors.
D) medulla oblongata.
E) skin.
50) Heat loss is promoted by
A) sweating, dilation of cutaneous blood vessels, and nonshivering thermogenesis.
B) dilation of cutaneous blood vessels.
C) sweating and dilation of cutaneous blood vessels.
D) nonshivering thermogenesis.
E) sweating.
51) Prediabetes is a condition that will likely become diabetes if eating and exercise habits are not altered.
True B) False
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Classify each scenario below as to primarily which type of work is being done.
52) maintaining a concentration gradient across a membrane
53) working on a dock, loading and unloading boxes into trucks all day
54) wound healing, recovering from surgery
55) enlarging one's muscles through body-building exercises
56) bringing glucose molecules inside brain cells so one can think
57) a thoroughbred horse, or greyhound dog, running around the track
Match each term to its definition.
58) a series of interconnected chemical reactions
59) reactions that result in the breakdown of large biomolecules
60) reactions that result in the synthesis of large molecules
Match the nutrient to its primary fate.
61) used immediately for energy
62) synthesis of tissues
63) storage
mechanical work
transport work
chemical work
biochemical pathway
catabolic pathway
64) the sum of all the body's chemical reactions
65) large molecules synthesized from smaller ones
66) large molecules broken into smaller ones
catabolism
anabolism
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
67) The energy content of a food or similar substance is measured by a process called . 67)
68) The represents the minimum resting energy expenditures of an awake, alert individual. 68)
69) Measuring oxygen consumption as a way of estimating a person's metabolic rate is one form of 69)
70) A diet of pure carbohydrate would produce an RQ of 70)
71) Metabolism is often divided into , energy-producing reactions, and , energy-utilizing reactions. 71)
72) The enzyme converts triglycerides into free fatty acids and glycerol. 72)
73) The lipoprotein most likely to be called "good (or healthy) cholesterol" is . 73)
74) are lipoprotein and lipid complexes that are formed in the intestine to carry lipids into circulation. 74)
75) Lipoproteins that contain large amounts of cholesterol for transport to peripheral tissues are called 75)
76) are unstable molecules that are formed during normal metabolism and are thought to contribute to aging, disease, and some cancers. 76)
77) are molecules that prevent damage to our cells by stopping the destructive effects of free radical formation. 77)
78) Triglycerides are broken down into , which feeds into glycolysis, and , which are metabolized to acetyl CoA. 78)
79) The pancreatic hormone that increases blood glucose concentration is 79)
80) The process of synthesizing glucose from noncarbohydrate precursors such as amino acids is called 80)
81) The process of glycogen synthesis is known as 81)
82) is the amount of heat generated during the digestion of a meal. 82)
83) is a condition of insulin deficiency from beta cell destruction. 83)
84) is known as insulin-resistant diabetes. 84)
85) The loss of water in the urine due to unreabsorbed solutes is known as 85)
86) is a test used to measure the body's insulin response to an ingested glucose load. 86)
87) The combination of type 2 diabetes, atherosclerosis, and high blood pressure is called 87)
88) monitor skin temperature and core body temperature. 88)
89) The production of heat from rhythmic tremors of skeletal muscle is referred to as 89)
90) Chemicals known as are fever-producing cytokines that are part of the normal immune response. 90)
91) A genetic condition in which body temperature becomes abnormally elevated is . 91)
92) is the direct transfer of heat energy from one object to another. 92)
93) is the transfer of heat energy to air. 93)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
94) After ingestion of carbohydrates in an insulin-deficient diabetic, would happen.
A) ketone production
B) glycolysis
C) fat synthesis
D) protein breakdown
E) protein breakdown and ketone production 94)
95) Drugs used to treat diabetes may
A) stimulate beta-cell secretion of insulin.
B) stimulate digestion and absorption of carbohydrates in the intestine.
C) decrease responsiveness of target tissue to insulin.
D) stimulate hepatic glucose output.
E) None of these answers are correct. 95)
96) In the fasted state, which statement is FALSE?
A) Some amino acids will be deaminated.
B) Adipose breaks down its store of triglycerides.
C) Skeletal muscle will increase gluconeogenesis.
D) Pyruvate and lactate are transported to the liver to make glucose.
97) The level of ketone bodies in the blood increases when high levels of are being metabolized.
A) carbohydrates
B) glucose
C) amino acids
D) fatty acids
E) proteins
98) The Atkins and South Beach diets are considered ketogenic because
A) Type I diabetics use them.
B) they have the potential to increase blood pH.
C) they cause the body to burn calories from noncarbohydrate sources.
D) they require people to eat large quantities of ketones.
E) they shift metabolism to increased glycolysis.
99) When blood levels of glucose, amino acids, and insulin are high, and glycogenesis is occurring in the liver, the body is in the
A) stress state.
B) bulimic state.
C) postabsorptive state.
D) absorptive state.
E) fasted state.
100) If you were in a desert without a food source, which nutrient would you like to have stored in your body in a large amount?
A) glycogen
B) vitamin B6
C) protein
D) fat
E) calcium
101) Which symptom would you expect to observe in a person with type 1 diabetes mellitus?
A) ketoacidosis
B) glucosuria
C) hyperglycemia
D) thirst and polydipsia
E) All of these answers are correct.
102) In type 2 diabetes mellitus, insulin levels are frequently normal, yet the target cells are less sensitive to the effects of insulin. This suggests that the target cells
A) have adequate internal supplies of glucose.
B) are impermeable to insulin.
C) cannot convert insulin to an active form.
D) may have a problem in their signal transduction pathway.
E) None of these answers are correct.
103) Which drug would be an effective way to lower plasma cholesterol levels?
A) a drug that stimulates intestinal cholesterol transport
B) a drug that adds plant sterols and stanols to the diet
C) a drug that binds to bile acids and prevents them from being reabsorbed
D) a drug that binds to bile acids and prevents them from being reabsorbed or a drug that adds plant sterols and stanols to the diet
E) a drug that stimulates the enzyme HMG coA reductase
104) Two males are the same age and ethnic background. While being tested for their BMR, Ibrahim consumes 20 liters of oxygen/hour and Yusuf consumes 16 liters of oxygen/hour. Which of the two needs to consume the most calories in order to maintain proper health and constant weight?
A) Ibrahim B) Yusuf
105) On a tour of African countries, Dom contracts a bad case of traveler's diarrhea. Because he cannot eat very much, his body starts to use energy sources other than carbohydrates. This would result in
A) ketosis.
B) increased gluconeogenesis in the liver.
C) decreased blood pH.
D) increased levels of urea in the blood.
E) All of these answers are correct.
106) Both insulin and glucagon are peptide hormones that target liver cells. The responses of the target cells to these two hormones are the opposite of each other. This information implies that
A) both hormones interact with receptors at the cell nucleus.
B) one of the hormones does not interact with a membrane receptor.
C) each of the two hormones uses a different second messenger.
D) one hormone binds to a receptor on the cell membrane and the other to an intracellular receptor.
107) Brown fat
A) functions in nonshivering thermogenesis.
B) contains a rich vascular supply.
C) is innervated by the sympathetic nervous system.
D) is found in infants.
E) All of these answers are correct. 107)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
108) List and discuss two different theories about the regulation of food intake and the role of signal molecules and the brain.
109) In the study by Morewedge et al., subjects that imagined eating 30 M&M's one at a time ate fewer real M&M's than subjects who thought about eating only 3 M&M's. What possible reason can you think of to explain this observation?
110) Explain why glucose should NOT be the sole source of energy in our diets. What is the best approach to meeting energy needs?
111) Explain the relationship among chylomicrons, cholesterol, and the various forms of lipoproteins (LDL-C, HDL-C, etc.). What is the role of each one in the body? Why are some considered "bad" and others "good"? Where does each come from? Where could each end up?
112) It is known that exercise is good for diabetics. Explain how GLUT4 transporters may be involved in this beneficial effect of exercise.
113) Compare and contrast the two types of diabetes mellitus.
114) Compare and contrast insulin and glucagon.
115) Why does insulin deficiency lead to metabolic acidosis?
116) Explain how and why abnormal temperatures, either too high or too low, can be dangerous.
117) Define basal metabolic rate (BMR), and list the six factors affecting BMR.
118) The weather person tells us that the temperature is 95, but the heat index is 103 and a heat advisory is in effect. What does this mean? Is humidity high or low? Why does it matter? Who is most affected, and why? What are some steps one could take to adjust?
119) Marta suffers from anorexia nervosa. One afternoon she is rushed to the emergency room because of cardiac arrhythmias. Her breath has the smell of an aromatic hydrocarbon (sweet, fruity odor), and blood and urine samples indicated ketonemia and ketonuria. Why do you think she is having the arrhythmias?
120) The crew of an ocean-going racing sailboat must adhere to strict weight limits for both their bodies and the food they eat, yet their activity levels are very high, and weather conditions may vary to extreme cold, so they must consume many kilocalories. What kinds of nutrient-dense foods can you suggest to them to bring? In general, what type of energy nutrient should they choose to consume?
121) Damien, in training for the Boston marathon, finds his plasma cholesterol concentration is somewhat increased. What other test results should Damien review before changing his training regime or diet?
122) Salazar has insulin-dependent diabetes mellitus. Salazar has an accident on his bike and breaks his arm. Would his insulin dosage change?
123) Haile has a blood test that shows a normal level of LDLs but an elevated level of HDLs in his blood. Since his family has a history of cardiovascular disease, he wonders if he should modify his lifestyle. What would you tell him?
124) Low leptin levels have been observed in athletes with chronic negative energy balance. What might be a possible explanation for this? Would you expect neuropeptide Y (NPY) levels to be high? Explain.
125) Describe a ketogenic diet. What are the pros and cons of such a diet? How is ketosis related to diabetes mellitus?
126) High protein (low carbohydrate) diets have become popular in recent years. Based on what you have learned about metabolism and the body's energy needs, explain what might be some of the disadvantages of this type of diet.
127) Kadija and Sally have been best friends since high school. Each is 5'5" tall and weighs about 160 lbs., which is considered to be overweight. Kadija's blood pressure is 125/82 and her blood analysis shows healthy levels of glucose and lipids. Sally's blood pressure is 135/87 and her blood analysis shows elevated glucose and triglycerides. Given that they are the same height and weight, would you expect their blood analyses to be more similar? Explain. Would you expect their body shapes to be similar? Explain. Which one is more likely to be diagnosed with metabolic syndrome? Explain.
128) There is only one way to lose weight without actually removing a body part: consume fewer calories than you expend. Is this statement true or false? Explain, citing a fundamental law of physics. Why is it difficult for many people to lose weight? Many weight-loss methods work for a short time. Explain why they work, and why they may not work forever.
129) Describe anorexia nervosa and diabetes mellitus, and how they resemble each other.
130) Prior to the discovery of the role of insulin in metabolism and the development of insulin therapy to treat diabetes mellitus, a diagnosis of this disease was always fatal. What do untreated diabetics die from?
131) Misty is 16 and, with her family, is visiting her grandmother for Christmas. At the end of a week surrounded by tempting holiday food, Misty weighs herself and sees that she has gained five pounds. She confides to her mother that she ate all of a 1-lb box of chocolates on Christmas day, but didn't overeat in any other way. There are 500 kilocalories per 100 g of chocolate. 1 lb = 454 g. There are 3500 kilocalories in a pound of fat. How many calories did she consume? Does this account for the five pounds she gained? Explain.
132) Calculate the body mass index of a woman who is 5'5" tall and weighs 180 lbs. Now calculate the BMI of a man with those dimensions. 1 kg = 2.2 lbs, 1 m = 39.24 in. Is either individual considered obese? Explain. Could BMI be misleading as a means of indicating obesity? Explain.
Answer Key
Testname: UNTITLED41
1) A
2) B
3) C
4) B
5) B
6) E
7) C
8) D
9) C
10) A
11) D
12) E
13) A
14) C 15) C
16) A
17) A
18) A
19) A
20) A
21) C
22) D
23) D
24) D
25) C
26) C
27) E
28) C
29) A
30) D
31) B
32) D
33) E
34) A
35) B
36) E
37) B
38) B
39) B
40) A
41) B
42) A
43) A
44) B
45) B
46) A
47) C
48) D
49) A
50) C
Answer Key
Testname: UNTITLED41
51) A
52) B
53) A
54) C
55) C
56) B
57) A
58) B
59) C
60) A
61) A
62) C
63) B
64) C
65) B
66) A
67) direct calorimetry
68) resting metabolic rate (RMR)
69) indirect calorimetry
70) 1.0
71) catabolic pathways, anabolic pathways
72) lipoprotein lipase
73) HDL or HDL-C
74) Chylomicrons
75) low-density lipoproteins (LDLs) or LDL-C
76) Free radicals
77) Antioxidants
78) glycerol, fatty acids
79) glucagon
80) gluconeogenesis
81) glycogenesis
82) Diet-induced thermogenesis
83) Type 1 diabetes mellitus
84) Type 2 diabetes mellitus
85) osmotic diuresis
86) Glucose tolerance test
87) metabolic syndrome
88) Thermoreceptors
89) shivering thermogenesis
90) pyrogens
91) malignant hyperthermia
92) Conductive heat loss
93) Convective heat loss
94) E
95) A
96) C
97) D
98) C
99) D
100) D
101) E
102) D
103) D
104) A
105) E
106) C
107) E
108) The hypothalamus contains two centers that regulate food intake: the feeding center and the satiety center, which inhibits the feeding center. The glucostatic theory states that glucose utilization by hypothalamic centers regulates food intake. The lipostatic theory states that signals from the body's fat stores to the brain modulate eating behavior to maintain a particular weight. Leptin is a protein hormone synthesized in adipocytes and may signal the brain to halt feeding behavior. Neuropeptide Y is a brain neurotransmitter that appears to be the stimulus for food intake; this molecule is inhibited by leptin. Ghrelin is a peptide secreted by the stomach that stimulates hunger. Figure 22.1 in the chapter summarizes peptides involved in feeding.
109) Psychological factors, such as "imagined" satisfaction from pretending to eat the candy, (or imagined guilt from all the calories and sugar that would have been consumed). Physiological factors may include signals released by the cephalic phase of digestion, just thinking about food, which could then affect the body's perceived input. (Chapter 21)
110) Given that glucose only meets energy rather than other essential nutrient needs, a person consuming only glucose would die of malnutrition. A mixture of fats, proteins, simple sugars, and complex carbohydrates optimizes the storage, nutrient, and caloric needs of the various organ systems. Glucose requires a relatively large amount of water for hydration and a large amount of space for storage. Glycogen is more compact, and fat is the most compact and efficient means of energy storage.
111) Chylomicrons are complexes composed of triglycerides, cholesterol, and lipoprotein, assembled in the intestinal epithelium. Most lipoprotein in blood is low-density, or LDL; other forms include very low-density (VLDL) and highdensity lipoprotein (HDL). The triglyceride portion of chylomicrons is a source of free fatty acids and monoglycerides for cells, which use them for energy or convert them back to triglycerides for energy storage. Cholesterol is a precursor for steroid hormones and bile components and, along with phospholipids synthesized fromfatty acids, a structural component of cell membranes. LDLs are a means of transporting cholesterol to most cells, whereas HDLs transport cholesterol primarily to the liver. LDL is "bad" or "lethal" because elevated LDL is associated with atherosclerosis. HDL is "good" or "healthy" because it takes cholesterol to the liver, where it is metabolized orexcreted.
112) When one exercises, skeletal muscles are utilized. Once they are active, they no longer require insulin to be able to take up glucose from the blood. This is due to the fact that exercise causes more GLUT4 transporters to be inserted into the membrane of the muscle cells. Thus, exercise is able to remove the excess glucose from the bloodstream of diabetics.
113) Type I diabetes mellitus is a condition of insulin deficiency due to pancreatic beta cell destruction. Type 2 diabetes mellitus is insulin-resistant, due to a variety of causes. Both result in increased blood glucose when insulin cannot stimulate the installation of GLUT transporters into the plasma membranes of skeletal muscle and adipose cells. Figure 22.20 in the chapter provides a detailed summary of the characteristics of type I diabetes.
114) Answers will vary but should include information in Tables 22.1 and 22.3 in the chapter. Answers could include information such as the release of both are stimulated by changes in blood glucose, insulin to increased blood glucose and glucagon to decreased blood glucose. Both are secreted by cells in the islets of Langerhans, insulin from beta cells and glucagon from alpha cells, etc.
115) Insulin deficiency produces a fasted-state metabolism. The liver metabolizes fatty acids for its energy needs, producing ketones. The ketones enter the blood, then are absorbed by tissues and converted to acetyl CoA. Ketones themselves are strong acids, thus ketoacidosis results. Other tissues begin to produce lactic acid, due to their anaerobic state resulting from loss of access to glucose.
116) The body's responses to high and low temperature are summarized in Figures 22.22 and 22.23 in the chapter. Complications include severe dehydration, loss of enzyme function, and death. Hypothermia is associated with slowed metabolism and loss of consciousness, and death.
117) BMR is an individual's lowest metabolic rate, which occurs when a person is sleeping. Factors affecting BMR are age and gender, amount of lean muscle mass, activity level, diet, hormones, and genetics.
118) The humidity is high, thus slowing evaporative heat loss; the heat advisory means take it slow and suggests you plan your day around the heat and try to get out of it. Elderly people are most likely to be affected physiologically and possibly economically and sociologically as well. Use fans and/or air conditioning, swim, take advantage of a mall or movie theater's air conditioning, decrease activity, do outdoor work only in the early morning or late evening.
119) It appears that Marta is suffering from ketoacidosis as a consequence of her anorexia. Because she is literally starving herself, her body is metabolizing large amounts of fatty acids and amino acids to provide energy and in the process is producing large quantities of ketone bodies (normal metabolites from these catabolic processes). One of the ketones that is formed is acetone, which can be eliminated through the lungs. This accounts for the smell of aromatic hydrocarbons on Jill's breath. The ketones are also converted into keto acids such as acetic acid. In large amounts this lowers the body's pH. As the kidneys excrete excess H+ , they reabsorb K+ , leading to a state of hyperkalemia. This is probably the cause of her arrhythmias. See the Running Problem throughout the chapter, including its conclusion.
120) A nutritionist's nightmare, this crew gets to eat foods everyone else is trying to avoid. Fat is high in kilocalories, but lightweight and doesn't occupy much space. Candy bars, granola with lots of nuts, and peanut butter are all good foods to have available, while vegetables, salads, and regular breakfast cereals are too bulky for the calories they provide.
121) Exercise often increases the levels of HDL's, since that is how fats travel throughout the body in order to be mobilized and used. Thus, his total cholesterol may be high, but it is better to depend on his HDL levels and the ratio of HDLs to LDLs.
122) Salazar will need increased levels of insulin. Insulin will promote the necessary healing by supporting anabolic pathways needed for regrowth of the bone. Students will learn in chapter 23 that prolonged stress (rather than the stress just at the time of the accident) will lead to increased blood glucose levels due to increased cortisol secretion, hence additional insulin will be needed to compensate for this as well.
123) Based just on the information given, Haile would appear to be in good health, at least relative to his diet and exercise. Problems are associated with elevated levels of LDLs, which carry cholesterol to peripheral tissues and make it available for the formation of atherosclerotic plaques in blood vessels. High levels of HDLs indicate that a considerable amount of cholesterol is being removed from the peripheral tissues and carried to the liver for disposal. You should encourage Charlie not to change, and keep up the good work.
124) Leptin is believed to provide negative feedback to the hypothalamus and result in decreased food intake. Therefore, in a state where food intake is too low, it would make sense that leptin levels would be low. NPY, however, appears to be a stimulus for food intake. Therefore, in these athletes, we would expect NPY to be high.
125) A ketogenic diet is low in carbohydrate and high in protein and fat. Ketone bodies are produced as fat is metabolized. Pros: rapid initial weight loss and caloric restriction. Cons: initial weight loss represents loss of glycogen and water, rather than fat; dehydration, vitamin and mineral deficiency; and kidney problems. Untreated diabetics cannot metabolize carbohydrates normally, so their diets are functionally ketogenic.
126) Low carbohydrate diets shift the body to a fasting mode because glucose is needed for the brain, central nervous systems, and red blood cells. After glycogen stores have been depleted, the body will convert protein and fats into glucose and ketone bodies to provide the energy needed. The disadvantages of this shift are excess ketone bodies can seriously disrupt the body's pH balance (lead to ketosis) and loss of protein from body tissue (this occurs even when abundant protein from food is provided).
127) Blood amounts of glucose and lipids are more related to the location than to the amount of extra fat, so height and weight alone do not predict blood analysis results. The body is largely composed of bone, lean muscle mass, fat, and water. Because each of these substances has different densities, it is possible for two people to have the same weight, but a different body composition. Based on the blood work, Sally is more likely to have upper-body fat (apple shape) and/or less lean muscle mass and Kadija is more likely to have lower-body fat (pear shape) and/or more lean body mass. Sally is at greater risk for metabolic syndrome, and appears to have it, based on her weight, BP, and blood glucose and lipids.
128) The statement is true, and is a principle of physics known as the first law of thermodynamics. It is difficult for many people to lose weight because of a variety of factors, such as overeating due to psychological factors, sedentary lifestyles, and so on. Weight-loss gimmicks work because ultimately they either reduce calories or increase activity, or both. They may be difficult to maintain because the novelty wears off, people feel deprived of food, and a multitude of other factors. Answers to this question will vary considerably.
129) Anorexia nervosa is lack of adequate caloric intake due to distorted body image. Diabetes mellitus results from lack of insulin and consequent inability to utilize glucose. Both diseases result in starvation if left untreated.
130) Figure 22.20 in the chapter provides a good summary of the effects of untreated diabetes mellitus. Metabolic acidosis and circulatory failure from dehydration are the primary triggers of death.
131) She consumed 454 g of chocolates. 454 g × 500 kcal/100g = 2270 kcal. The chocolates cannot account for more than about 2/3 of a pound. She must have consumed extra calories at her meals and other snacks as well, and she may have exercised less than normal.
132) BMI is kg/m2 1 kg/2.2 lb × 180 lb = 81.8 kg. 5 ft × 12 in/ft = 60 in.
1 m/39.24 in × 65 in = 1.66 m. 81.8 kg/(1.66m)2 = 29.7.
BMI calculation is the same for both genders, but the classification for obesity is not. For men, a BMI greater than 25 is o for women a BMI greater than 30 is obese. Based on this, only the man is considered obese, but the woman is on the bor BMI does not take into account the amount of lean weight versus fat weight, so a very fit and muscular person could be classified as obese based on BMI but will not have obesity-related health problems.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) The action of a hormone on a target cell involves effects on
A) receptor proteins.
B) lipids.
C) receptor proteins and lipids.
D) receptor and nonreceptor proteins.
E) nonreceptor proteins.
2) The endocrine gland that is modified sympathetic ganglia is the
A) posterior pituitary.
B) adrenal cortex.
C) adrenal medulla.
D) thyroid.
E) anterior pituitary.
3) All of the hormones secreted by the adrenal gland play a major role in growth and metabolism.
A) True B) False
4) Cholesterol is the starting material for the synthesis of
A) estradiol.
B) progesterone.
C) aldosterone.
D) calcitonin.
E) progesterone, aldosterone, and estradiol.
5) Crossover effects are sometimes seen among
A) steroid hormones.
C) most hormones.
6) The ACTH is synthesized from
A) TRH.
B) MSH.
C) CRH.
D) beta-endorphin.
E) POMC.
7) The adrenal medulla secretes
A) androgens.
B) corticosteroids.
C) glucocorticoids.
D) mineralocorticoids.
E) catecholamines.
B) peptide/protein hormones.
D) all hormones.
8) Which could describe the function of 11 β-hydroxysteroid dehydrogenase?
A) An enzyme located in renal tubules that acts on cortisol.
B) It converts cortisol to a form with a lower specificity for mineralocorticoid receptors there.
C) It aids in preventing crossover effects from cortisol.
D) It converts cortisol to a less active form.
E) All of these answers are correct.
9) Cortisol secretion is highest between and
A) noon, early evening
C) early morning, noon
10) CRH stimulates the release of
A) MSH.
B) ACTH.
C) cortisol.
D) DHEA.
E) None of these answers are correct.
11) Cortisol has which effects?
B) midnight, early morning
D) early evening, midnight
A) suppresses the immune system and causes positive calcium balance
B) suppresses the immune system and influences brain function
C) influences brain function
D) causes positive calcium balance
E) suppresses the immune system
12) Without cortisol's permissive effect on , an animal would die.
A) aldosterone
B) thyroid hormone
C) glucagon
D) parathyroid hormone
E) insulin
13) Melanocortins includes one or more of the following.
A) ACTH
B) growth hormone
C) MSH
D) cortisol
E) ACTH and MSH 13)
14) Thyroid hormone contains the mineral
A) thallium. B) iron. C) iodine. D) sodium. E) zinc.
15) The C cells of the thyroid gland produce
A) calcitonin and thryoxine.
B) only thyroxine.
C) only TSH.
D) only parathyroid hormone.
E) only calcitonin.
16) Pendrin is an anion transporter important in the production of
A) TRH.
B) thyroid hormone.
C) parathyroid hormone.
D) calcitonin.
E) TSH.
17) Iodine uptake into thyroid cells involves symport with A) chloride. B) sodium. C) potassium. D) hydrogen. 17)
18) Thyroid hormones
A) are lipophilic.
B) are hydrophilic and must bind to plasma proteins for transport to target cells.
C) must bind to plasma proteins for transport to target cells.
D) are lipophilic and must bind to plasma proteins for transport to target cells.
E) are hydrophilic.
19) The thyroid hormones T3 and T4 do not use transporters to cross cell membranes.
A) True B) False
20) Which transports thyroid hormones into target cells?
A) TRPV6
B) Mineralocorticoid receptor
C) Sodium-iodide symporter
D) MCT8
E) CaSR (calcium sensing receptor)
21) The pituitary hormone that stimulates synthesis of thyroid hormone from the thyroid gland is A) ACTH. B) TRH C) CRH. D) TSH. E) FSH.
22) Hyperthyroidism
A) increases protein catabolism.
B) decreases oxygen consumption.
C) causes cold intolerance.
D) decreases protein synthesis.
E) slows heart rate.
23) The effects of thyroid hormone on peripheral tissue include
A) increased activity of osteoclasts.
B) decreased oxygen consumption.
C) increased adrenergic effects in the heart.
D) decreased heart rate.
E) All of these answers are correct.
24) GH
A) is secreted by the anterior pituitary.
B) is secreted by the anterior pituitary and binds to a plasma protein.
C) is secreted by the posterior pituitary.
D) is secreted by the posterior pituitary and binds to a plasma protein.
E) binds to a plasma protein.
25) Hypersecretion of growth hormone in adults can cause
A) exophthalmus.
B) goiter.
C) diabetes.
D) giantism.
E) acromegaly.
26) Somatostatin is another name for
A) thyroid hormone.
B) growth hormone-releasing hormone.
C) growth hormone-inhibiting hormone.
D) growth hormone.
E) insulin-like growth factor.
27) Hypersecretion of growth hormone before puberty could result in
A) rickets.
B) cretinism.
C) giantism.
D) dwarfism.
E) osteoporosis.
28) Mature, less active bone cells are called
A) osteocytes.
B) osteons.
C) osteoclasts.
D) osteoblasts.
E) chondrocytes.
29) Intestinal calcium enters epithelial enterocytes during transcellular transport using
A) a sodium-iodide transporter.
B) osteoclasts.
C) CaSR (calcium sensing receptor).
D) an amino acid transporter (MCT8).
E) apical calcium channels (TRPV6 or ECaC).
30) Parathyroid hormone
A) increases the rate of calcium absorption.
B) decreases the rate of calcium excretion.
C) stimulates osteoclast activity.
D) increases the level of calcium ion in the blood.
E) All of these answers are correct.
31) The parathyroid glands produce a hormone that
A) increases white blood cells.
B) increases calcium ions in the blood.
C) increases sodium ions in the blood.
D) increases glucose in the blood.
E) increases potassium ions in the blood.
32) Increased calcium in the blood stimulates secretion of which hormone?
A) calcitonin
B) thyroid hormone
C) growth hormone
D) parathyroid hormone
E) testosterone
33) A condition that decreases bone mass or density to lead to weakened bones and fractures is
A) osteitis.
B) cretinism.
C) acromegaly.
D) osteoporosis.
E) osteomyelitis.
34) Calcium reabsorption at the kidneys is increased by the hormone
A) cortisol.
B) calcitonin.
C) aldosterone.
D) calcitriol.
E) ADH.
35) A hormone that can lower blood levels of calcium ion is
A) parathyroid hormone.
B) thyroxine.
C) calcitonin.
D) oxytocin.
E) glucagon.
36) Parathyroid hormone is
A) the cause of Graves' disease.
B) an peptide hormone.
C) dissolved in plasma.
D) bound to a carrier.
E) a lipid.
37) Vitamin D (calcitriol) is
A) formed by sunlight and synthesis is stimulated by high calcium levels.
B) formed by sunlight only.
C) bound to plasma protein for transport only.
D) synthesis is stimulated by high calcium levels.
E) formed by sunlight and bound to plasma protein for transport. 37)
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the disease with the description.
38) hypercortisolism
39) hyperthyroidism
40) involves endocrine stimulation by antibodies
41) Some symptoms mimic diabetes mellitus.
42) associated with overactive osteoclasts
43) Calcitonin may be an appropriate treatment.
44) may be an autoimmune disease affecting the adrenal gland
45) may result from adrenal tumor
46) may result from a pituitary tumor
Match the condition with the description
47) associated with Graves' disease
48) caused by growth hormone deficiency in childhood
49) caused by growth hormone excess in adulthood
50) mental retardation associated with hypothyroidism in infancy
51) This condition results from excess androgens in females.
Match the condition with its description
52) caused by growth hormone excess in childhood
53) hunchback appearance with osteoporosis
54) puffy appearance under the eyes with hypothyroidism
55) easily observable symptom of hypercortisolism
56) can be caused by increased TSH
A) myxedema
B) giantism
C) kyphosis D) goiter
E) moon face
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
57) Structurally similar steroids sometimes bind to the same receptor, producing effects. 57)
58) Cortisol secretion shows a pattern of secretion, normally peaking in the 58)
59) The hypothalamic-pituitary-adrenal pathway begins with secretion of into the and transported to the . 59)
60) The most important metabolic effect of (a long term stress hormone) is protection against , crucial to surviving significant stress because of the increased metabolic rate involved with the stress response. 60)
61) The thyroid gland is made up of many that produce and store thyroid hormones. 61)
62) Thyroid hormones are made from the amino acid . 62)
63) ACTH is synthesized from a large glycoprotein called , which also produces the opiod in the pituitary. 63)
64) What are the two distinct endocrine cell types in the thyroid gland, and what do they secrete? 64)
65) is a result of deficient thyroid hormone secretion in infancy. 65)
66) List four factors that affect normal body growth. 66)
67) GH stimulates the secretion of from the liver and other tissues. This hormone has feedback effect on growth hormone secretion. 67)
68) In bone, the calcium phosphate forms crystals of 68)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
69) Name four physiological functions of calcium.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
70) Damage to cells of the zona fasciculata of the adrenal cortex would result in
A) decreased ability to convert fatty acids to glucose.
B) the disappearance of axillary and pubic hair.
C) increased water retention.
D) increased volume of urine formation.
E) decreased levels of sodium ion in the blood.
71) Increased cortisol would NOT cause which of the following?
A) increased levels of fatty acids in the blood
B) increased rate of glucose synthesis by the liver
C) increased rate of glycogen storage by the liver
D) suppression of the immune system
E) increased ACTH levels
72) Premature closure of the epiphyseal plates could be caused by
A) low levels of thyroxine.
B) high levels of growth hormone.
C) high levels of calcium in the diet.
D) high levels of sex hormones.
E) high levels of vitamin D3.
73) Increased blood calcium levels result in increased
A) osteoclast activity.
B) retention of calcium by the kidneys.
C) secretion of calcitonin.
D) secretion of parathyroid hormone.
E) excitability of neural membranes. 73)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
74) Pick one hormone from Chapter 23 and design a concept map showing the feedback pattern, types of hormone receptors and how this relates to normal cellular / tissue responses, and areas in the map which could be the cause of pathologies (i.e., hyposecretion, hyperresponsiveness).
75) Draw a map of steroid hormone synthesis.
76) Describe the hypothalamic-pituitary-endocrine organ pathways for the adrenal cortex and thyroid gland. Do releasing and/or trophic hormones have effects outside this pathway? Explain.
77) What is a permissive hormone effect? Provide an example, explaining what would result if the permissive hormone was absent.
78) Explain how cortisol suppresses the immune system, and why this is sometimes a useful therapy. What are some negative side effects of cortisol therapy? Why do doctors prescribe cortisol in doses that taper off at the end of the therapy period? Why do doctors sometimes prefer to prescribe nonsteroidal anti-inflammatory drugs?
79) Javier has been serving in a noncombat position in the army for two years and has just been informed that he is leaving on a combat mission tomorrow. Javier is feeling very stressed. How has his endocrine system responded to this bad news? Which hormones are involved, and what effects do they have?
80) List the effects of cortisol.
81) Which hormones of growth and metabolism have a permissive effect on other hormones of growth and metabolism?
82) What are the three common causes of hypercortisolism?
83) What are the symptoms and causes of Cushing's disease? What are the symptoms and causes of Addison's disease?
84) Explain how the mutant agouti mouse is proving useful as a model for obesity-related disease.
85) Define hypertrophy and hyperplasia, and describe their hormone regulation.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
86) Bill does not begin puberty until he is 16. What effect would you predict this will have on his height?
A) Bill will probably be taller than if he had started puberty earlier.
B) Bill will probably be shorter than if he had started puberty earlier.
C) Bill will have bones that are denser than if he had started puberty earlier.
D) The late onset of puberty will have no effect on Bill's height.
E) Bill will probably be a dwarf.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
87) Describe the endocrine regulation of bone growth.
88) Describe the sources, targets, and primary effects of the hormones of calcium metabolism.
89) Describe differences in effects of hormones of growth and metabolism in children compared to effects in adults.
90) Precocious puberty in girls can result from hypersecretion of nongonadal steroids. In such girls, there is early breast development, onset of menses, and ovulation of viable eggs. This can occur by age 7 or even earlier. Which hormone(s) and nongonadal endocrine gland(s) may be responsible? Can the responsible gland(s) be safely removed? Explain. How might this condition be treated without surgery? What permanent nonsexual consequences may result from not treating this condition?
91) Carmen has just given birth to her third child, and as with the first two, she stayed home and used the services of a nurse-midwife. While her recovery from the births of the first two children was normal and she was able to breast-feed both for two years, she is not lactating this time and is experiencing other difficulties. Her symptoms also include vomiting, fatigue, cold intolerance, and myxedema, which worsen over the coming weeks. She ignored her midwife's suggestion to see her doctor the day after giving birth, but has finally gone to an Ob-Gyn during the third week after giving birth. Her newborn baby is healthy and thriving on human breast milk purchased from a milk bank. Diagnostic tests show decreased amounts of several hormones, as well as edema and poor blood flow into the pituitary. What do her symptoms indicate? Which hormones are likely decreased? What may be the root cause?
92) In an effort to impress her physiology instructor, your roommate did an Internet search on cortisol. In her excitement, she did not read the book chapter, classroom activities have not yet focused on this chapter, and she knows next to nothing about this hormone. She discovers unrelated therapeutic effects such as treatment for bee stings and rejection of transplanted organs. However, you completed your physiology course last semester, and she turns to you for help. What can you tell her about some other therapeutic uses for cortisol, and what functional connections do these illustrate? What are some of the negative side effects?
93) Therapeutic surgical removal of the thyroid gland was documented more than 1000 years ago. In the 19th century, a surgeon performing that procedure had only about 50% patient survival, and patient death was often unrelated to nonspecific complications such as infection or bleeding. What condition of the thyroid is so easily diagnosed that ancient surgeons would think to remove it? What hormonal problem unrelated to thyroid hormones may account for the 50% mortality of thyroidectomy patients in the 19th century (and probably throughout history)? Why didn't the surgeons anticipate this problem? Why wasn't the mortality closer to 100%?
94) A diagnosis of thyroid cancer may be treated with removal of the thyroid gland. Which hormone or hormones may now be deficient? Considering each hormone individually, which ones should be restored and why? Explain any age-related considerations. Which nonthyroid hormone may be affected by careless thyroidectomy? Explain your answer, indicating whether or not it is critical to maintain this hormone.
95) Jorge is suffering from hypothyroidism. How could his physician determine if his symptoms result from problems at the level of the hypothalamus and pituitary or at the level of the gland itself?
96) An adult with cretinism has incomplete puberty (e.g., scant pubic hair), abnormal facial features, dwarfism, and mental retardation. Explain what causes these symptoms. How is cretin dwarfism different from pituitary dwarfism? How could cretinism be prevented?
97) The approach to treating patients who secrete abnormal amounts of hormone sometimes depends upon the age of the patient. List the hormones of growth and metabolism for which this statement is true, and explain in each case how and why the approach would differ for a prepubertal patient compared to a postpubertal patient.
98) Juan has great hopes that his 12-year-old son will play professional basketball and wants to do anything that might be helpful. He has heard that the administration of testosterone or other androgens might increase his son's height. Alarmed, you tell him that this may be a treatment that would actually limit his future athletic potential. Why?
99) Rani has read how important Ca2+ ions are to muscle contraction and neuron function. Rani, age 25, hates milk and most dairy products, and does not think she eats many foods that are sources of calcium, nor does she take supplements. Why don't Rani's muscles and nerves show problems related to calcium deficiency? What problems might Rani encounter later in life if she continues this lifestyle?
100) Khan is in the emergency room, complaining of severe back pain and pain when trying to urinate. The physician has ordered blood tests and urinalysis to measure levels of parathyroid hormone (PTH) and phosphates. What possible reason would the physician have for doing this? What would the physician conclude if the results of the blood test show high levels of PTH and calcium and the urinalysis shows high levels of phosphate? How are calcium and phosphates related?
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
101) Which can cause increased osteoclast activity?
A) Inhibition of RANKL
C) Inactivation of the RANK receptor
B) Increased release of PTH
D) None of the above
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
102) are responsible for bone deposition while are responsible for bone break down. 102)
Answer Key
Testname: UNTITLED46
1) D
2) C
3) B
4) E
5) A
6) E
7) E
8) E
9) C
10) B
11) B
12) C
13) E
14) C 15) E
16) B
17) B
18) D
19) B
20) D
21) D
22) A
23) C
24) B
25) E
26) C
27) C
28) A
29) E
30) E
31) B
32) A
33) D
34) D
35) C
36) B
37) E
38) C
39) B
40) B
41) C
42) D
43) D
44) A
45) C
46) C
47) D
48) C
49) E
50) A
Answer Key
Testname: UNTITLED46
51) B
52) B
53) C
54) A
55) E
56) D
57) crossover
58) circadian or diurnal, morning
59) corticotropin-releasing-hormone (CRH), hypothalamic-hypophyseal portal system, anterior pituitary (See Figure 23.2 in the chapter.)
60) cortisol, hypoglycemia
61) thyroid follicles
62) tyrosine
63) pro-opiomelanocortin (POMC), β-endorphin
64) C cells secrete calcitonin, and follicle cells secrete thyroid hormones.
65) Cretinism
66) 1. growth hormone and other hormones
2. adequate diet
3. absence of chronic stress
4. genetics
67) insulin-like growth factor, negative
68) hydroxyapatite
69) 1. signal molecule
2. part of intercellular cement that holds cells together at tight junction
3. cofactor in the coagulation cascade
4. affects the excitability of neurons
See Figure 23.11(b) in the chapter.
70) A
71) E
72) D
73) C
74) The primary hormones covered are adrenal glucocorticoids (Fig. 23.2), thyroid hormones (Fig. 23.5) and calcitonin (Tbl. 23.1), growth hormone (Fig. 23.8), parathyroid hormone (Fig. 23.12), and calcitriol (Fig. 23.14). If the hormone uses a cell membrane receptor, then the effects should be fairly rapid and short-lived. If the hormone uses an intracellular or nuclear receptor, then the effects will take longer and be longer lasting, as this will typically involve gene transcription. (See Chapter 6, Signal Pathways.)
75) See Figure 23.1 in the chapter.
76) See Figures 23.2 and 23.5 in the chapter. CRH and ACTH receptors have been identified in cells of the immune system and are thought to mediate the association between stress and the immune system.
77) A permissive hormone effect is the dependence of one hormone on the presence of another in order to fully exert its effects. An example is that cortisol is required for full glucagon effect. Without cortisol, glucagon cannot adequately perform its role in glucose regulation, and death results.
78) Cortisol prevents cytokine release and antibody production by white blood cells and decreases leukocyte mobility and migration; cortisol is thus an effective anti-inflammatory and antirejection drug for transplant patients. Cortisol weakens the skeleton and alters brain function, in addition to suppressing the immune system. Because cortisol suppresses ACTH production by negative feedback, the adrenal cortex atrophies during cortisol therapy. Tapering off of dosing allows adrenal cortex function to return gradually. Nonsteroidal anti-inflammatories avoid the negative side effects of cortisol therapy and are therefore more appropriate for minor inflammation.
79) Increased cortisol secretion by the adrenal cortex is stimulated via corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH). Cortisol generally has catabolic effects, to protect against hypoglycemia. These effects include gluconeogenesis in the liver, breakdown of skeletal muscle proteins, enhanced lipolysis, immune suppression, and bone loss. Additionally, this discouraging news may be accompanied by a fight-or-flight reaction, in which increased sympathetic activity will result in increased heart and respiratory rates, increased perfusion of skeletal musculature, and decreased digestive activity.
80) Effects include promoting gluconeogenesis, breakdown of skeletal muscle proteins and lipolysis, immune suppression, negative calcium balance, alteration of cerebral function.
81) Cortisol is required for glucagon to be fully effective against a hypoglycemic challenge. In children, thyroid hormone is necessary for the full expression of growth hormone.
82) 1. adrenal tumor autonomously secretes cortisol (primary hypercortisolism)
2. pituitary tumor autonomously secretes ACTH (secondary hypercortisolism)
3. iatrogenic hypercortisolism (physician-caused)
83) Cushing's disease is hypercortisolism, which can arise from adrenal or pituitary tumors or exogenous administration of cortisol. Symptoms include gluconeogenesis and consequent hyperglycemia, tissue wasting (especially in the limbs) from breakdown of protein and fat, excess fat deposition in trunk and face, mood elevation followed by depression, and difficulty with learning and memory. Addison's disease, far less common, is hyposecretion of cortisol as well as other adrenal steroids. It is usually caused by autoimmune destruction. Symptoms include darkening of the skin due to effects of ACTH on melanocytes.
84) See the "CRH and ACTH Have Additional Physiological Functions " section of the chapter.
85) Hypertrophy is increase in cell size, and hyperplasia is increase in cell number. Both are regulated by growth hormone, thyroid hormone, and insulin.
86) A
87) Bone growth is regulated by many hormones, including growth hormone, insulin-like growth factor, sex steroids, and hormones that regulate calcium metabolism.
88) Parathyroid hormone, calcitonin, and calcitriol are the primary hormones. See Table 23.1 and Figures 23.12, 23.13 and 23.14 in the chapter.
89) While all the hormones discussed in this chapter will have effects on adults and children, some have very specific effect different stages of life.
1. Cortisol provides a catabolic protective effect against hypoglycemia, enhancing the effectiveness of glucagon, import response to stress. In children, excess cortisol released due to stress can result in stunted growth or a failure to thrive.
2. Thyroid hormone provides substrates for oxidative metabolism in adults, but has the additional effect of providing fo expression of growth hormone and mental development in infants and young children. In adults, Thyroid hormones ca protein catabolism while it has anabolic effects in children. Thyroid hormone deficiency in children will be developmen delayed and short in stature and may have mental retardation. In adults, hypothyroidism may cause cold-intolerance, slow reflexes, fatigue, slow heart rate, and many other conditions.
3. Growth hormone is anabolic, essential for tissue growth and maintenance. Its effects are most dramatically seen in ch (rapid growth spurts). Growth hormone deficiency causes dwarfism and excess causes giantism in children. Acromegal characterizes GH excess in adults.
4. Calcitonin's primary role is likely in providing normal skeletal growth in children. In adults it is important when net bone deposition is needed, such as during pregnancy.
90) Adrenal sex hormones include estrogens. Hypersecretion of estrogen would stimulate puberty. The adrenal glands can be removed, if cortisol and aldosterone are replaced. Drugs such as aromatase inhibitors, which block estrogen production, may be appropriate. An effect of estrogen is stimulation then cessation of skeletal growth, which after precocious puberty could result in shorter final stature due to premature closure of growth plates in long bones.
91) A lack of several pituitary hormones is apparent: PRH stimulates prolactin secretion and lactation, vomiting and fatigue could indicate lack of ACTH and consequent cortisol, and cold intolerance and myxedema indicate lack of TSH and consequent thyroid hormone. Abnormal function of the anterior pituitary can result from lack of hypothalamic-releasing hormones, pituitary adenoma, or pituitary infarction related to pregnancy (Sheehan syndrome; this syndrome is not described in the text, but the student may be able to reason decreased pituitary function due to decreased blood flow).
92) Cortisol suppresses the immune system by preventing cytokine release, inhibiting antibody production, and inhibiting the inflammatory response. Allergic reactions to bee stings, poison ivy, and pollen involve the immune system; thus cortisol can be used to suppress these responses. Rejection of a transplanted organ is also an immune response. Negative feedback from the exogenous hormone inhibits ACTH production, which can result in atrophy of the adrenal cortex. Hypercortisolism can also result, with symptoms similar to diabetes mellitus, and extra fat deposition leading to "moon face," and changes in mood and cognition.
93) Goiters develop from lack of iodine in the diet or from Graves' disease, producing an obvious enlargement in the neck. Loss of parathyroid hormone following thyroidectomy with inadvertent parathyroidectomy caused death in patients due to lack of calcium for excitable cells such as heart and nerve cells. The role of the parathyroid glands was not fully understood in the 19th century. Mortality was not 100% because the amount of parathyroid tissue varies in individuals, and some had parathyroid tissue that was not removed by thyroidectomy.
94) The thyroid gland is the source of thyroid hormones and calcitonin. Thyroid hormones should be replaced in children to maintain normal growth and in adults to maintain quality of life. Calcitonin replacement is not necessary in adults, because parathyroid hormone and calcitriol should be unaffected, and they are sufficient to maintain normal calcium balance. It is unclear how important calcitonin replacement may be in children. Careless thyroidectomy could result in removal of parathyroid glands. If parathyroid hormone is not restored, death results.
95) The physician could order blood tests to determine the levels of TSH, T3, and T4 in the blood. If the condition is due to disease of the thyroid gland, you would expect to see elevated levels of TSH because of a lack of feedback inhibition by thyroid hormones. If, on the other hand, the problem is due to problems at the level of the hypothalamus or pituitary, you would expect to see decreased levels of TSH.
96) Cretinism results from lack of thyroid hormones during early childhood. Thyroid hormones are permissive for growth hormones and play an important role in the development of the nervous system. The incomplete puberty may be related to lack of thyroid hormone and growth hormone effects on the sexual tissues. Pituitary dwarfism results from lack of growth hormone, unrelated to thyroid hormones. Prevention of thyroid cretinism is aimed at adequate prenatal care (especially dietary iodine) and administration of exogenous thyroid hormones to the infant.
97) Thyroid hormone and growth hormone are the main hormones of growth and development with differing roles in child compared to adulthood. Students may wish to discuss calcitonin as well, but there is little detail in the text and incompl understanding of its role, especially in adults.
1. Thyroid hormone is essential for normal growth and development in children, although this hormone is not essential living, regardless of age. Thyroid imbalances must be promptly corrected in children, or else the patients will be developmentally delayed. Thyroid hormone has a permissive effect for growth hormone, is anabolic in children, and is required for normal neural development. These effects are not seen with thyroid hormone imbalance in adulthood, but to maintain a normal quality of life, amount of circulating thyroid hormone should be corrected in adults as well.
2. Children cannot grow normally without adequate amounts of growth hormone, and imbalances should be corrected promptly. Secretion of GH peaks during the teens. Excess GH in childhood can lead to giantism, while lack of GH leads pituitary dwarfism. Lack of GH in adulthood is not problematic, but excess production stimulates the growth of cartilag causing acromegaly.
98) The administration of sex hormones may cause a quick increase in height, but could also contribute to the premature closure of the epiphyseal plates, limiting the final height this child may attain.
99) Rani's skeleton contains enough Ca2+ to, under the influence of PTH, release Ca2+ to maintain normal blood levels. The muscles, nerves, and other cells are thus able to obtain sufficient Ca2+ . It is also likely that Rani consumes at least small amounts of Ca2+ in her diet. Rani will eventually lose enough bone density to be prone to fractures.
100) Based on the symptoms that Khan is experiencing, the physician is likely considering kidney stones to be the cause of severe back pain. If there is a problem with hypersecretion of parathyroid hormone, this would cause increased calcium levels in the blood, and cause the kidneys to exchange more phosphates for calcium, leading to high urine levels of phosphates. If calcium levels in the blood are very high, the kidney will not be able to reabsorb all of the calcium, leading to the formation of kidney stones out of calcium phosphate.
101) B
102) osteoblasts, osteoclasts
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Which is NOT a pathogen?
A) athlete's foot fungus
B) meningococcus bacterium
C) chicken pox virus
D) hookworm parasite
E) cancer
2) Autoimmune diseases are an example of a(n) response by the immune system.
A) lack of
C) overactive
B) incorrect
D) None of the answers are correct.
3) When the immune system creates a response that is out of proportion to the threat it has been exposed to, the response is called an
A) allergy or hypersensitivity reaction.
B) autoimmune response.
C) immunodeficiency.
4) Antibiotics are drugs that destroy or inhibit the growth of
A) bacteria.
B) viruses and bacteria.
C) viruses, bacteria, and multicellular pathogens such as hookworms.
D) multicellular pathogens such as hookworms.
E) viruses.
5) Viruses
A) easily survive in the environment outside the body.
B) are parasitic.
C) must reproduce inside host cells.
D) must reproduce inside host cells, are parasitic, and easily survive in the environment outside the body.
E) must reproduce inside host cells and are parasitic.
6) Which is NOT matched correctly?
A) active immunity - an immune response started and developed by the cells
B) adaptive immunity - responses directed toward specific invaders
C) innate immunity - nonspecific responses
D) active adaptive immunity - immunity passed through the placenta or milk to offspring
E) Each of these is correctly described.
7) Lymphoid tissues include
A) lymph nodes.
B) spleen.
C) bone marrow.
D) thymus.
E) All of the answers are correct.
8) The largest lymphoid organ(s) is/are the
A) GALT.
B) thymus.
C) lymph nodes.
D) tonsils.
E) spleen.
9) Diffuse lymphoid tissue includes
A) GALT (gut-associated lymphoid tissue).
B) tonsils, GALT (gut-associated lymphoid tissue), and the spleen.
C) tonsils.
D) the spleen.
E) tonsils and GALT (gut-associated lymphoid tissue).
10) Swelling and soreness of the lymph nodes indicate that
A) immune cells are fighting infection.
B) dangerous cancerous changes are occurring in the immune system.
C) the immune system is incapable of working.
D) too much or improper exercise has been undertaken.
E) None of the answers are correct.
11) are clusters of lymphatic nodules located beneath the epithelial lining of the small intestine.
A) Lymph nodes
B) Tonsils
C) Peyer's patches
D) Adenoids
E) Immune complexes
12) Cells of the mononuclear phagocyte system include
A) macrophages and monocytes.
B) macrophages, monocytes, neutrophils and eosinophils.
C) macrophages, monocytes, neutrophils, eosinophils, lymphocytes and plasma cells.
D) lymphocytes and plasma cells.
E) neutrophils and eosinophils.
13) Which cell is NOT correctly matched with the characteristic?
A) eosinophils - numbers increase with allergies and parasites
B) eosinophils - cytotoxic cells may live only 6-12 hours
C) neutrophils - most difficult to identify
D) basophils - have granules
E) neutrophils - most abundant white cell
14) are the precursor cells of macrophages.
A) Eosinophils
B) Basophils
C) Monocytes
D) Lymphocytes
E) Neutrophils
15) Which are NOT antigen-presenting cells (APCs)?
A) dendritic cells
B) neutrophils
C) monocytes
D) macrophages
E) lymphocytes
16) Leukocytes recognize molecules that are unique to pathogens; thus, the molecules are
A) antigens.
B) pathogen-associated molecular patterns.
C) pattern recognition receptors.
D) toll-like receptors.
E) phagosomes.
17) Chemical signals that attract immune cells are known as
A) opsonins.
B) chemotaxins.
C) lysozymes.
D) antigens.
E) interferons.
18) Which immune cells are also known as Langerhans cells?
A) mast cells
B) eosinophils
C) basophils
D) dendritic cells
E) lymphocytes
19) Lymphocytes and plasma cells
A) mediate the adaptive immune response.
B) all function the same way.
C) are found mostly in lymphoid tissue.
D) mediate the adaptive immune response and are found mainly in lymphoid tissue.
E) mediate the adaptive immune response, are found mainly in lymphoid tissue, and all function the same way.
20) C-reactive protein is a type of
A) pyrogen.
B) cytokine.
C) acute-phase protein.
D) granzyme.
E) chemotaxin.
21) Which is NOT a characteristic of adaptive immunity?
A) acquired immunity
C) humoral immunity
B) cell-mediated immunity
D) nonspecific immunity
22) Cytokines function by
A) attracting immune cells and causing fever and poisoning and killing invading cells.
B) attracting immune cells and causing fever, poisoning and killing invading cells, and digesting invading cells.
C) poisoning and killing invading cells.
D) attracting immune cells and causing fever.
E) digesting invading cells.
23) Chemotaxins function in
A) digesting invading cells, attracting additional immune cells, and poisoning and killing invading cells.
B) digesting invading cells.
C) attracting additional immune cells.
D) poisoning and killing invading cells.
E) digesting invading cells and attracting additional immune cells.
24) A substance that induces fever is known as a(n)
A) acute phase protein.
B) chemotaxin.
C) cytokine.
D) opsonin.
E) pyrogen.
25) Opsonins function by
A) marking or tagging pathogens so phagocytes can find and ingest them.
B) poisoning and killing invading cells and marking or tagging pathogens so phagocytes can find and ingest them.
C) poisoning and killing invading cells, marking or tagging pathogens so phagocytes can find and ingest them, and digesting invading cells directly.
D) digesting invading cells directly.
E) poisoning and killing invading cells.
26) Acute phase proteins are produced by the
A) macrophages.
B) liver.
C) thymus.
D) lymphocytes.
E) lymph nodes.
27) The cells responsible for the production of circulating antibodies are
A) helper T cells.
B) cytotoxic T cells.
C) NK cells.
D) suppressor T cells.
E) plasma cells.
28) Passive immunity is a type of immunity.
A) innate
B) adaptive
29) The cells responsible for cell-mediated immunity are the A) T lymphocytes.
C) suppressor T lymphocytes.
B) B lymphocytes.
D) plasma cells.
30) Stem cells that will form B lymphocytes are found in the
A) kidneys.
B) bone marrow.
C) spleen.
D) thymus.
E) liver.
31) The initial cellular defense against pathogens are the
A) plasma cells.
B) phagocytes.
C) B lymphocytes.
D) NK cells.
E) T lymphocytes.
32) Which acts as first line of defense against pathogens?
A) inflammation B) skin
33) An inflammatory response is triggered when
A) T lymphocytes release interferon.
B) red blood cells release pyrogens.
C) blood flow to an area increases.
D) neutrophils phagocytize bacteria.
E) mast cells release granules containing histamine.
C) macrophages D) lymphocytes
34) Lymphocytes that attack body cells infected with viruses are
A) B lymphocytes.
B) helper T cells.
C) cytotoxic T cells.
D) suppressor T cells.
E) plasma cells.
35) Cells that help to influence other immune cells are
A) NK cells.
B) helper T cells.
C) B lymphocytes.
D) cytotoxic T cells.
E) plasma cells.
36) The cells that are actively involved in immune surveillance are the A) plasma cells.
B) helper T cells.
C) suppressor T cells.
D) NK cells.
E) B lymphocytes.
37) Stem cells that will form T lymphocytes mature in the A) thymus.
B) liver.
C) spleen.
D) kidneys.
E) bone marrow.
38) is the immunoglobulin class that make up 75% of antibodies in adult blood. A) IgA B) IgD C) IgE D) IgG E) IgM
39) Immunoglobulins that cross the placenta are A) IgA. B) IgD. C) IgE. D) IgG. E) IgM.
40) Immunoglobulins that attach to mast cells and are involved in allergic reactions are A) IgA. B) IgD. C) IgE. D) IgG. E) IgM.
41) Immunoglobulins that are found on the surface of B lymphocytes and may play a role in regulation of the humoral immune response are A) IgA. B) IgD. C) IgE. D) IgG. E) IgM.
42) Immunoglobulins in early responses to pathogens are A) IgA. B) IgD. C) IgE. D) IgG. E) IgM.
43) Immunoglobulins in external secretions are A) IgA. B) IgD. C) IgE. D) IgG. E) IgM. 43)
44) The specificity of an antibody is determined by the A) antibody class.
B) fixed segment.
C) variable region.
D) size of the antibody.
E) antigenic determinants.
45) For a lymphocyte to respond to an antigen, the antigen must
A) be phagocytized by the lymphocyte.
B) bind to the DNA of the lymphocyte.
C) enter the cytoplasm of the lymphocyte.
D) depolarize the lymphocyte.
E) bind to specific receptors on the lymphocyte membrane. 45)
46) When an antigen fragment is bound to a MHC class I molecule to form a MHC-I-antigen complex, it can stimulate a A) NK cell.
B) cytotoxic T cell.
C) B cell.
D) plasma cell.
E) helper T cell. 46)
47) MHC class II molecules are found
A) only on red blood cells.
B) only on granulocytes and macrophages.
C) only on dendritic cells and macrophages.
D) on all cells with a nucleus.
E) only on liver cells and macrophages in the spleen.
48) A person's blood type is determined by the
A) number of specific molecules on the cell membrane.
B) chemical character of the hemoglobin.
C) shape of the red blood cells.
D) size of the red blood cells.
E) presence or absence of specific glycoprotein molecules on their cell membrane.
49) A person with type A blood has
A) anti-B antibodies in his plasma.
B) anti-A antibodies on his red blood cells.
C) the ability to receive AB blood cells.
D) anti-B antibodies on his red blood cells.
E) anti-A antibodies in his plasma.
50) Overactive immune responses to antigens are
A) immunodeficiency diseases.
B) allergies and hypersensitivity reactions.
C) the result of stress.
D) autoimmune diseases.
E) common in the elderly.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the cell type with its description.
51) These are the most abundant leukocyte; they are formed in the bone marrow.
52) Cytotoxic, these cells are associated with allergic reactions and parasitic infections.
53) Precursors of macrophages, these cells are relatively rare in blood.
54) These cells are related to mast cells, and both release chemical mediators, which aid in the inflammatory and immune responses.
55) Estimated to reach populations of one trillion in normal adults, most of these cells are foun in lymphoid tissues. These cells look similar to one another under the microscope, but function differently.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
56) A patient has increased eosinophils and monocytes but normal levels of neutrophils, basophils, and lymphocytes. Which is the most likely cause of these test results?
A) a chronic parasitic infection
B) a chronic bacterial infection
C) a viral infection
D) a severe allergic reaction
E) an acute bacterial infection
57) A patient has increased neutrophils and macrophages with normal levels of basophils, eosinophils, and lymphocytes. Which is the most likely cause of these test results?
A) an acute viral infection
B) an allergic reaction
C) an autoimmune reaction
D) a fungal infection
E) a chronic bacterial infection
58) A patient with hay fever symptoms for a couple weeks comes to your office to be treated for his hay fever. If a white blood cell differential count was performed, which leukocytes would likely be increased?
A) neutrophils, monocytes, and lymphocytes B) monocytes, eosinophils, and basophils
C) lymphocytes, basophils, and neutrophils D) monocytes, lymphocytes, and eosinophils
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the type of immunity to its description.
59) present at birth
60) Secreted lysozyme kills bacteria.
innate
58)
61) NK cells cause apoptosis of viral-infected cells.
62) Antibodies in breast milk protect a newborn baby from pathogens.
63) Infected cells are killed by perforin and granzymes.
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
64) macrophages are phagocytic cells that are permanent residents of specific tissues and organs. 64)
65) are fixed macrophages found in the brain.
66) are fixed macrophages found in the liver.
67) are dendritic cells found in the skin.
68) are free phagocytes found in the lungs.
69) The ability of certain cells to mobilize in response to changes in their chemical environment is called 69)
70) Substances that trigger an immune response are known as
are antibodies.
72) The process by which the surface of a microorganism is covered, making it more likely to be phagocytized occurs when act as opsonins.
73) cells enable the immune system to respond more quickly if the same antigen is encountered a second time.
74) exists when the immune system does NOT respond to a particular antigen on cells of the body.
75) are mediators released from white blood cells that act on other white blood cells and mediates innate defenses.
76) are cytokines that inhibit the replication of viruses. 76)
77) are groups of lymphocytes bind to a particular ligand.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
78) A sample of tissue from an injury shows a large number of basophils. This would indicate that the tissue was
A) being rejected.
B) abscessed.
C) inflamed.
D) infected by multicellular parasites.
E) infected by viruses.
79) Meghan thinks she has an abscessed tooth. If she does, which type of white blood cell would you expect to see in increased numbers in a differential count?
A) eosinophils
B) lymphocytes
C) basophils
D) monocytes
E) neutrophils
80) Ricardo wants to determine his blood type, so he takes a few drops of blood from his finger and mixes it with various antibodies. His blood cells agglutinate when mixed with the anti-A antibody but not with the anti-B antibody. Therefore, which is true?
A) His plasma would cross-react with type O red blood cells.
B) His plasma contains B antibodies.
C) He could receive type B blood in a transfusion.
D) He is Rh positive.
E) He could donate blood to an individual with type B blood.
81) In an experimental situation focused on the development of a new vaccine, mice were injected with a viral antigen. Their plasma was removed in order to detect the presence of antibodies. This is an example of
A) innate immunity.
B) passive immunity.
C) active immunity.
D) natural immunity.
E) autoimmunity.
82) In an experimental situation, a virus is injected into a rabbit and the rabbit is allowed to make antibodies against the viral antigen. These antibodies are then removed from the rabbit plasma and injected into a human to help fight the same viral disease. This is an example of
A) passive immunity.
B) active immunity.
C) autoimmunity.
D) innate immunity.
E) natural immunity. 82)
83) A decrease in which lymphocytes would decrease all parts of an immune response?
A) helper T cells
B) B lymphocytes
C) regulatory T cells
D) plasma cells
E) cytotoxic T cells
84) The human immunodeficiency virus (HIV) that causes the disease known as AIDS selectively infects
A) suppressor T cells.
B) cytotoxic T cells.
C) plasma cells.
D) helper T cells.
E) B cells.
85) Milly has just received a kidney transplant and is taking cyclosporin A, a drug that inhibits cytotoxic T cells. What does this medication do?
A) prevents rejection
B) prevents inflammation from destroying the transplanted kidney
C) decreases hematopoiesis
D) increases the number of antibodies in the blood
E) None of the answers are correct.
86) Athena has a bad sore throat and the lymph nodes in her neck are swollen. This indicates
A) the focus of the infection is the lymph nodes.
B) the affected lymph nodes contain an increased number of lymphocytes.
C) the lymph gland has increased its secretion of thymosin.
D) lymph is not flowing through these lymph nodes.
87) Anil accidentally swallows a substance that activates the complement cascade in the absence of bound antibodies. This substance would
A) produce a fever.
B) increase circulation of lymph.
C) cause extensive cellular damage.
D) prevent inflammation.
E) activate blood clotting. 87)
88) In a routine examination, some blood is taken and analyzed. The results show a high IgM level for the mumps antigen. This would indicate the
A) person is immune to mumps.
B) person is just coming down with mumps.
C) person is allergic to mumps.
D) person has just recovered from mumps.
E) None of the answers are correct.
89) A fluid sample contains a large amount of IgA type antibody. This fluid is probably
A) plasma.
B) intracellular.
C) lymph.
D) tears.
E) blood.
88)
89)
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the immunoglobulin to its description.
90) crosses the placenta
91) present in breast milk
92) receptors on B lymphocytes
93) binds to mast cells, triggering degranulation
94) reacts to blood group antigens
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
95) Draw and label a typical antibody molecule. Be sure to include the light chain, heavy chain, Fab, Fc, and the hinge region. Identify the antigen-binding site and disulfide bonds.
96) Describe differences between bacteria and viruses.
97) Compare and contrast the effectiveness of the immune response to bacterial and viral infections.
98) Explain the role of exposure to antigens in the development of the immune system in the fetus and in the primary and secondary immune responses in children and adults. How does this compare to the role of innate immunity?
99) Describe innate and adaptive immunity.
100) Describe the role of complement in immunity.
101) Explain clonal expansion and the roles and interactions of effector cells, memory cells, naive lymphocytes, and plasma cells.
102) Explain the roles and interactions of each of the following in immunity: B lymphocytes, antibodies, immunoglobulins, T lymphocytes, MHC, HLA.
103) Explain each of these terms: antibiotic, antibody, antigen, antihistamine, antiviral drug.
104) Draw a concept map illustrating the immune response to bacterial infection.
105) Draw a concept map illustrating the immune response to a viral infection.
106) Describe the various functions of antibodies in an immune response.
107) Describe how a virus is inhibited in an immune response.
108) Describe the functions of cytotoxic T cells and NK cells.
109) The retrovirus HIV frequently mutates, making it difficult for scientists to develop a single effective vaccine. When flu vaccines are administered, patients are told that they are only protected from one strain or a few strains of the flu and are still as susceptible to other strains as unvaccinated people. Explain why.
110) Three different patients go in to see their gynecologist for some persistent, bothersome symptoms: Betelhem, Quinnie, and Armelle. Betelhem's doctor has detected benign uterine fibroid tumors. Quinnie's doctor has detected early-stage malignant vaginal tumors. Armelles's doctor has detected late-stage malignant ovarian tumors. Which part of the immune system would respond to these conditions? What would analysis of the nearby lymph nodes of these women show? What is the prognosis for each woman? Explain.
111) Jens has just been exposed to the measles virus, and he cannot remember if he has had measles before. He asks you if there is any way he can tell if he has been previously exposed or if he is going to get sick. What would you tell him? Why won't he get sick from a second infection?
112) Compare and contrast inflammation and infection.
113) Zoonotic diseases are transmissable from animals to humans. These include ringworm, a fungus which infects pets and people; plague, a bacterial disease resulting from a flea bite to mammals including humans; and rabies, a viral disease of the central nervous system that affects all mammals and is almost always fatal. On the other hand, the feline immunodeficiency virus has no effect on humans, and human immunodeficiency virus has no effect on cats, though each may be deadly to its normal host. Describe what may prevent cross-species infection in some cases and allow it in others.
114) Barun is 6 months old and requires a blood transfusion; his blood type is B. What type of blood may he receive? Is his age a factor in your answer? What would happen if he received a "wrong" blood type? If Barun were younger, is it possible that there is no "wrong" blood type? Why may it surprise a beginning physiology student, familiar with the basics of immunology, that a person could mount an immediate immune response to transfused blood? Explain all of your answers.
115) The HIV blood test detects anti-HIV antibodies. Why do viruses stimulate antibody production? How effective are antibodies against viruses, as compared to bacteria? How are viral infections normally eliminated in the body? Why does a person's immune response fail to eliminate life-long viral infections such as HIV and herpes? Explain all of your answers.
116) What do virus-infected cells and cancer cells have in common, related to the type of immune response and its long-term effectiveness?
117) The rejection of a transplanted organ by the immune system of the recipient is a result of a cell-mediated immune response, rather than antibody-mediated response. What does this tell you about the transplanted cells? From the perspective of the T cell, are the cells of the transplanted organ significantly different from virus-infected or cancerous cells?
118) Sketch the graphs of plasma antibody concentration in a primary immune response and a secondary immune response. Explain the graphs.
119) Shannon just finished finals and is heading home for winter break, excited for all the holiday activities her family has planned. It was a really stressful week and she just wants to get home to her family and friends. The day after finals Shannon wakes up feeling very sick with a cold, sore throat and muscle aches, probably the flu. Her father says the stress from finals probably caught up with her and she just needs to rest. What do you think? Is Shannon's father right? Could stress have caused her to get sick? If not, why not? If so, what mechanisms were at play?
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
120) Which represents the body's first line of defense to a pathogen?
A) B cells B) leukocytes C) stomach acid D) neutrophils
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
121) Place the four basic steps of the immune response in the correct order.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
122) Which correctly explains the relationship between the nervous system, endocrine system, and immune system?
A) Cytokines from the immune system can affect neuroendocrine function.
B) Only the nervous system and immune system share common receptors.
C) Only the nervous system and endocrine system share common signal molecules.
D) Hormones and neuropeptides do not alter the function of immune system cells.
Answer Key
Testname: UNTITLED43
1) E
2) B
3) A
4) A
5) E
6) D
7) E
8) E
9) E
10) A
11) C
12) A
13) C
14) C 15) B
16) B
17) B
18) D
19) D
20) C
21) D
22) D
23) C
24) E
25) A
26) B
27) E
28) B
29) A
30) B
31) B
32) B
33) E
34) C
35) B
36) D
37) A
38) D
39) D
40) C
41) B
42) E
43) A
44) C
45) E
46) B
47) C
48) E
49) A
50) B
Answer Key
Testname: UNTITLED43
51) A
52) B
53) C
54) A
55) B
56) A
57) E
58) B
59) A
60) A
61) B
62) A
63) A
64) Fixed
65) Microglia
66) Kupffer cells
67) Langerhans cells
68) Alveolar macrophages
69) chemotaxis
70) antigens or immunogens
71) Immunoglobulins
72) antibodies
73) Memory
74) Self-tolerance
75) Interleukins
76) Interferons
77) Clones
78) C
79) E
80) B
81) C
82) A
83) A
84) D
85) A
86) B
87) C
88) B
89) D
90) B
91) A
92) D
93) E
94) C
95) See Figure 24.7(a) in the chapter.
96) Bacteria are independent cells with DNA that can survive and reproduce outside a host. Viruses are not cells, but rather are small pieces of DNA or RNA enclosed in a protein coat. Viruses can only survive and reproduce inside a host cell. Bacteria are susceptible to antibiotics. Viruses are treated with antiviral drugs. See Table 24.3 in the chapter.
97) Both pathogens are foreign and thus have antigens, therefore, they each stimulate both branches of the immune response. The humoral response is more effective at eliminating bacterial infections than viral infections because bacteria typically do not have self antigens. The cell-mediated immune response is more effective at eliminating viral infections than bacterial, because viruses infect and, therefore, alter self cells, and it is altered self cells that stimulate cytotoxic T cells.
98) During development, any lymphocytes bearing receptors that bind to molecules in the fetus are eliminated. Thus, the only lymphocytes that persist at birth are those that failed to bind to anything, that is, those that have never encountered an antigen. Once the immune system has matured (early in infancy), primary immune responses develop in response to never-before encountered antigens, and secondary immune responses develop with subsequent exposures to the same antigens. Innate immunity is, at all times, independent of prior antigen exposure.
99) Innate immunity is a nonspecific response to foreign invaders or tissue damage and acts as a second line of defense. Adaptive (acquired) immunity has two major methods of response, cell-mediated immunity and humoral immunity, both of which are specific to the pathogen. Cells of the adaptive immune system are responsible for immunological memory.
100) Complement proteins are part of a cascade producing a membrane attack complex that can lyse pathogens. Complement proteins stimulate other aspects of the immune response as well.
101) Clonal expansion is the increase in population of a lymphocyte of a particular antigen specificity, as a result of exposure to that antigen. Lymphocytes produced during clonal expansion differentiate either into effector cells, which produce the immune response and die within a few days, or memory cells, which persist for years and continue to reproduce. Naive lymphocytes are those present at birth, with antigen specificity already determined, but in small numbers because they have not yet been exposed to the antigen and undergone clonal expansion. Plasma cells are the effector B lymphocytes, which become specialized for producing and secreting large amounts of antibody.
102) The immune system consists of two main classes of cells: B lymphocytes and T lymphocytes. The effector B lymphocytes, plasma cells, are specialized for producing large amounts of a protein known as an antibody. Antibodies bind to specific antigens, leading to the destruction of the antigens and pathogens bearing the antigens. Immunoglobulins are just antibodies, categorized according to specific details of their structure and function. T lymphocytes are specialized for destroying cells that bear antigen within a self molecule known as MHC. MHC stands for major histocompatibility complex, which is a group of cell surface proteins essential for triggering the immune response. HLA stands for human leukocyte antigen, and is just an alternative name for MHC.
103) An antibiotic is a drug that kills bacteria. Antibodies are proteins produced by lymphocytes that help lead to destruction of invading pathogens. Antigens are molecules that stimulate an immune response. Antihistamines are drugs that block secretion of histamine from immune cells. Antiretroviral and antiviral drugs are drugs that destroy specific kinds of viruses.
104) Map content should resemble Figure 24.16 in the chapter.
105) Map content should resemble Figure 24.17 in the chapter.
106) Antibodies enhance phagocytosis through clumping and opsonization, neutralize bacterial toxins, activate complement, mediate inflammation, and activate immune cells.
107) A virus in the plasma may be inhibited due to antibody action (see the "Antibody Functions" section in the chapter). Host cells containing viruses are killed by cytotoxic T cells, through the action of perforin, granzymes, and a "death receptor" all of which lead to apoptosis. See also the "Viral Infections Require Intracellular Defense" section of the chapter.
108) Cytotoxic T cells bind to and destroy specific virus-infected cells, as part of the immune system. NK cells are part of the innate defenses, secreting antiviral cytokines and attacking host cells that lack MHC-I complexes as a result of a viral infection.
109) The specificity of vaccines to a particular antigen is critical in order to mount an appropriate immune response. In order to function effectively, both plasma cells and activated T cells must recognize a particular pathogen. Since HIV frequently mutates, several forms of the virus may be present and therefore a single drug may target one form but not another. The flu vaccine is developed early in the flu season after the virus affecting the first victims is characterized. If a person is infected with a different strain or with a mutated vaccine-related strain, the vaccine is ineffective.
110) (Note to instructor: Students must understand the difference between benign and malignant tumors, and that staging of tumors is related to prognosis. This question may be better for a comprehensive final exam or as an out -of-class assignment.) Uterine fibroid tumors are not cancer because they do not spread, hence the designation "benign." Nearby lymph nodes will contain no sign of uterine fibroids, and prognosis is independent of this condition because cancer is not indicated. No antigens are present, so there is no immune response. The other two women have cancer, and the cellmediated immune response would be stimulated. Early-stage cancers are often completely treatable, and nearby lymph nodes may show no sign of the cancer; prognosis is good. Late-stage ovarian cancer has likely spread, and lymph nodes would contain ovarian cancer cells. Prognosis is poor in this case, because presence of cancer cells in lymph nodes often indicates that the cells have spread to other organs, as well.
111) If Jens has previously had the measles, there should be a significant amount of IgG antibody in his blood shortly after the most recent exposure, as a result of a secondary humoral immune response. If he has not previously had the disease and is in the early stages of a primary response, his blood might show an elevated level of IgM type antibodies. These are the first to be produced in a primary response and are ultimately replaced by IgG antibodies. IgG antibodies are able to mount a more vigorous and immediate response to subsequent exposures, preventing illness.
112) Infection implies the presence and active growth of microorganisms, thus an infection could be of a bacterial, viral or fungal origin, with the organisms often stimulating inflammation at the site of the infection. Inflammation is characterized by redness, swelling, increased temperature, etc., but these symptoms are caused by one's own immune system, either fighting off the pathogen or repairing tissue damage, or both. It is also possible to have inflammation, such as with a sprained ankle, without infection.
113) Some pathogens require conditions that are species specific. In the case of viral infections, it may be that some species lack certain cell-surface markers that viruses bind to before they invade. In the case of a virus such as rabies, the virus may bind to a cell marker that is present in all mammalian neural tissue. Some pathogens may require specific chemical environments. The existence of zoonotic diseases underscores the common features of humans and nonhuman animals.
114) Barun may receive type B or type O blood. Type O lacks antigens to stimulate an immune response, and type B blood will not trigger an immune response in a type B person. It is possible that if Barun were newborn, he could receive any type, because he may not yet have antibodies to foreign blood, however this would not be a reasonable risk to take. The transfusion of incompatible blood would result in a humoral immune attack on the transfused blood, and this could be fatal. A beginning student may logically believe that there are no antibodies to blood antigens in the blood of a person who has never received a transfusion. Antibodies develop in the first few months of life, however, because of the presence of similar antigens on gut bacteria and food.
115) Viruses have antigens, thus they stimulate the humoral immune response as well as the cell -mediated response. Antibodies are less effective against viruses because viruses "hide" inside cells, and antibodies do not enter cells. Viral infections can be eliminated by the cell-mediated response, which destroys virus-infected self cells. Life-long virus infections are possible because some viruses persist inside of cells without altering them in a way that stimulates immune attack.
116) Both are treated as altered self cells by the immune system, and both cancer cells and viruses can undergo frequent mutations and thus can fail to be eliminated by the immune system.
117) Transplanted cells contain surface molecules recognized as self, as well as some recognized as non-self. As far as the T cell is concerned, the transplanted organ consists of antigens that are no different from those related to viruses or cancer.
118) Graphs should resemble Figure 24.13 in the chapter. In a primary response, antibody is not detectable until several days after exposure to antigen, and peak antibody concentration is lower than it is in a secondary response. The secondary response shows a more immediate and steep increase in concentration. This more rapid and vigorous response indicates that the memory cells retained following the first exposure proliferate more readily.
119) It is possible that stress can be part of the problem. Increased stress causes a raise in the levels of cortisol in the blood and cortisol can actually decrease antibody production, lymphocyte proliferation, and reduce the activity of natural killer cells. If she had been exposed to some pathogen like the flu virus, it is possible that the effects of the sympathetic nervous system could have suppressed symptoms while elevated, but also reduced the effectiveness of the immune system, so when the sympathetic rush was over after finals, she started to notice the signs of her infection.
120) C
121) 1. detection and identification of the pathogen; 2. communication with other immune cells to rally an organized; 3. recruitment of assistance and coordination of the response among all participants, and; 4. destruction or suppression of the pathogen.
122) A
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) The role of phosphocreatine is to
A) release energy.
B) transfer energy.
C) store energy.
D) store oxygen.
E) provide a substrate for gluconeogenesis.
2) Glycolytic metabolism is also known as
A) glycogenesis.
B) anaerobic metabolism.
C) aerobic metabolism.
D) beta-oxidation.
E) gluconeogenesis.
3) The substance in muscle fiber cytoplasm that directly powers muscle contraction is
A) fatty acids.
C) ATP.
4) The advantage of anaerobic metabolism is
A) high yield of ATP.
B) fast ATP production.
C) greater endurance.
D) greater use of fat stores.
E) fewer by-products.
B) glucose.
D) phosphocreatine.
5) If oxygen is NOT available for aerobic ATP production, builds up on muscles.
A) ATP
C) lactic acid/lactate
B) glucose
D) pyruvic acid/pyruvate
6) Excess postexercise oxygen consumption serves all of the following purposes EXCEPT it
A) removes unnecessary catecholamines from circulation.
B) metabolizes lactate.
C) replenishes oxygen bound to myoglobin.
D) restores ATP and phosphocreatine levels.
7) When the muscle has used up its stored ATP and glucose but continues to have a plentiful supply of oxygen, which process will it turn to next to produce more energy for muscle contraction?
A) protein catabolism
C) fatty acid β-oxidation
B) fermentation of glucose to lactate
D) ketosis
8) It takes approximately of aerobic exercise to begin mobilizing fats from adipose tissue.
A) 10 minutes
B) 45 minutes
C) 30 minutes
D) 60 minutes
E) 30 seconds
9) Fat stores are used for energy only after muscles have depleted their carbohydrate energy stores.
A) True
B) False
10) The largest metabolic reserves for the average adult are stored as
A) amino acids.
B) proteins.
C) fatty acids.
D) triglycerides.
E) carbohydrates.
11) The nutrients that yield the most energy per gram when metabolized are
A) carbohydrates.
B) fats.
C) proteins.
D) nucleic acids.
E) vitamins.
12) The process of creating glucose out of non-carbohydrate precursors to make more energy for exercise is referred to as
A) ketolysis.
C) glycolysis.
B) hydrosis.
D) gluconeogenesis.
13) Which hormone(s) increase(s) in concentration in the plasma during exercise?
A) catecholamines
B) insulin
C) cortisol
D) cortisol and catecholamines
E) cortisol, catecholamines, and insulin
14) Cortisol, the catecholamines, and growth hormone stimulate all of the following, EXCEPT
A) promote the conversion of triglycerides to glycerol and fatty acids.
B) mobilize glycogen from the liver.
C) enhance storage of fat in adipose tissue.
D) raise plasma glucose levels.
15) EPOC is
A) extraneous preoxygen contribution.
B) extra phosphorylated oxygenated creatine.
C) excess postexercise oxygen consumption.
D) exercising physiological oxygen consumption.
E) excess physiological oxygen contribution.
16) In resistance exercise, such as strength training, muscles rely heavily on energy production.
A) anaerobic
B) aerobic
17) With endurance training, muscle mitochondria increase in
A) size only.
C) size and number.
18) Exercise hyperventilation results from signals from
A) the carotid body chemoreceptors only.
B) activating pulmonary stretch receptors only.
B) neither size nor number.
D) number only.
C) muscle and joint mechanoreceptors and proprioceptors, the carotid body chemoreceptors, and activating pulmonary stretch receptors.
D) muscle and joint mechanoreceptors and proprioceptors and from the carotid body chemoreceptors.
E) muscle and joint mechanoreceptors and proprioceptors only.
19) During mild to moderate exercise, arterial pH, PO2, and PCO2 are
A) nearly half of normal.
B) almost twice as high as normal.
C) nearly normal.
20) The initial change in heart rate at the onset of exercise is due to
A) stretching of the cardiac muscle fibers in response to increased venous return.
B) overfilling of the ventricles.
C) decreased parasympathetic activity.
D) increased sympathetic activity.
21) Redistribution of blood flow during exercise results from
A) vasoconstriction in skeletal muscle and vasodilation in viscera.
B) vasodilation in skeletal muscle and vasoconstriction in viscera.
C) vasodilation only.
D) vasoconstriction only.
22) During exercise, sweating helps lose heat from the body through the process of
A) concentration.
B) conduction.
C) evaporation.
D) radiation.
E) convection.
23) When the concentration of sodium ion in the ECF increases,
A) there is a decreased thirst.
B) there is an increase in the volume of urine produced.
C) osmoreceptors are stimulated.
D) ADH secretion decreases.
E) aldosterone secretion increases.
24) During exercise, the most significant factor affecting the pH of body tissues is the production of
A) keto acids/ketone bodies.
B) carbon dioxide.
C) lactic acid/lacatate.
D) hydrochloric acid.
E) organic acids.
25) During increased exercise,
A) cardiac output decreases.
B) venous return increases.
C) stroke volume decreases.
D) vasoconstriction occurs at the active skeletal muscles.
E) All of the answers are correct.
26) Sweat glands contain
A) cholinergic receptors.
B) alpha-1 receptors.
C) beta receptors.
D) alpha-2 receptors.
E) All of the answers are correct.
27) With acclimatization, the body begins to do a better job of conserving
A) heat only.
B) water only.
C) salt only.
D) water and heat only.
E) water, heat, and salt.
28) Benefits of regular exercise include all of the following, EXCEPT
A) decreased risk of heart attack.
B) increased levels of LDL (low-density lipoproteins).
C) decreased blood pressure.
D) increased plasma levels of HDL (high-density lipoproteins).
E) decreased plasma levels of triglycerides.
29) There is clear evidence that strenuous exercise on a regular basis enhances the immune system.
A) True B) False
30) Which best explains why exercise can help decrease the need for insulin use in people with type II diabetes mellitus?
A) Exercise uses up blood sugar before its levels can become increased.
B) Exercise decreases cortisol levels.
C) Exercise up-regulates insulin receptors.
D) Exercise does not help type II diabetes.
31) During exercise, skeletal muscle
A) vasoconstriction increases peripheral resistance to blood flow.
B) vasodilation decreases peripheral resistance to blood flow.
C) vasoconstriction decreases peripheral resistance to blood flow.
D) vasodilation increases peripheral resistance to blood flow.
E) None of the answers are correct.
32) With heat acclimatization,
A) aldosterone increases.
B) aldosterone increases and sweating becomes more concentrated.
C) sweating increases and aldosterone increases.
D) sweating increases.
E) sweating becomes more concentrated.
33) During the first 15 seconds of intense exercise, such as sprinting or power lifting, most of the energy is provided by
A) carbohydrate oxidation.
B) ATP in muscle fiber and phosphocreatine.
C) phosphocreatine.
D) fat oxidation.
E) ATP in muscle fiber.
34) Which is involved in the pathway that causes an immediate increase in ventilation rate at the beginning of exercise?
A) Mechanoreceptors and proprioceptors in muscles send information to the motor cortex of the brain and widespread vasoconstriction causes increase in blood pressure.
B) Widespread vasoconstriction causes increase in blood pressure.
C) Output from the limbic system and cardiovascular control center triggers parasympathetic discharge and widespread vasoconstriction causes increase in blood pressure.
D) Mechanoreceptors and proprioceptors in muscles send information to the motor cortex of the brain.
E) Output from the limbic system and cardiovascular control center triggers parasympathetic discharge.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the response to the description
35) percent fat metabolized for ATP production as exercise intensity increases
36) arterial PO2 during mild to moderate exercise compared to rest
37) peripheral vascular resistance during exercise
decrease
no change
38) mean arterial pressure during exercise
39) relative depression of immune system with change from moderate to strenuous exercise
40) plasma glucose concentration 30 minutes after glucose ingestion in diabetics who exercise, compared to those who do not
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
41) The adaption of the body to repeated exercise in hot environments occurs through a process called 41)
42) What two effects does sympathetic stimulation have on the heart during exercise? 42)
43) During exercise, skeletal muscle receives approximately % of blood flow. From where is this blood redistributed? 43)
44) The rise in body temperature triggers two thermoregulatory mechanisms: and 44)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
45) In addition to the number and type of muscle fibers in a muscle, peak athletic performance requires
A) good supply of nutrients.
B) adequate numbers of muscle mitochondria.
C) a well-developed respiratory system.
D) a good blood supply and system of blood delivery.
E) All of the answers are correct. 45)
46) Dehydration causes
A) increased thirst.
B) decreased secretion of vasopressin (ADH).
C) increased levels of aldosterone.
D) fluid to shift from extracellular fluid to intracellular fluid.
E) All of the answers are correct. 46)
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
47) How does exercise hyperventilation maintain nearly normal PO2 and PCO2? 47)
48) The maximal rate of consumption of is used as a measurement of a person's ability to perform endurance exercise and is measured in what units? How is this molecule related to metabolism? 48)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
49) Dmitri made a New Years resolution to get healthy, so he started an exercise plan. Early in the process he noticed that he fatigued quickly. As he continued to exercise regularly, he noticed that it took longer to fatigue. What change explains the increased endurance?
50) Why and how does intracellular K+ decrease with exercise?
51) List and briefly discuss advantages or improvements to metabolism from aerobic exercise.
52) Discuss changes in the cardiovascular and pulmonary systems that result from conditioning for exercise.
53) List and discuss the benefits of exercise, especially related to decreased risk of cardiovascular disease.
54) Explain the advantages and disadvantages of glycolytic metabolism.
55) Why is the normal baroreceptor reflex not activated during exercise?
56) During exercise, blood flow to the active skeletal muscles is increased by autoregulation. Propose a mechanism based on the need for nutrients that would explain how the autoregulation might take place.
57) Individuals with McArdle's disease cannot break down glycogen. How would this affect substrate utilization during exercise?
58) Alexsandra has hyperthyroidism. How might this affect ATP production during exercise?
59) Athletes with chronic energy deficit (energy output > energy intake) tend to have high levels of cortisol. Do you expect their immune systems would be better than those who are sedentary? Explain.
60) Based on what you learned in the chapter on control of blood flow and pressure, what happens to blood flow to meet the metabolic demands of exercising skeletal muscle? How is this accomplished? What is the predicted effect of this change on systemic blood pressure during exercise? What are the changes in heart function during exercise, and what effects should those changes have on systemic blood pressure? What happens to systemic blood pressure during exercise? Explain the apparent contradictions.
61) Sabrina's resting heart rate is 80 beats per minute, and her resting stroke volume is 50 mL per beat. What is her cardiac output? When she exercises, her heart rate increases to 100 beats per minute and her stroke volume increases to 55 mL per beat. What happens to her cardiac output? What is the advantage of the lower relative increase in stroke volume?
62) Daniella is a dancer trying to get into the New York City Ballet. She knows that it is very competitive, so she is practicing several hours a day. She also knows that ballet dancers need to be very thin, so she is restricting her diet to 600 calories a day and only eats fruits and vegetables. She continues her workout and dietary routine for several months, and on the day of her audition she feels very weak. She ends up fainting during her audition. As the athletic trainer and physician are evaluating Daniella, they notice that she has several bruises and frequent muscle spasms. Why is Daniella having all of these problems?
Answer Key
Testname: UNTITLED44
1) B
2) B
3) C
4) B
5) C
6) A
7) C
8) C
9) B
10) D
11) B
12) D
13) D
14) C
15) C
16) A
17) C
18) D
19) C
20) C
21) B
22) C
23) C
24) B
25) B
26) A
27) C
28) B
29) B
30) C
31) B
32) C
33) B
34) A
35) A
36) B
37) A
38) B
39) B
40) A
41) acclimatization
42) 1. increases contractility
2. increases heart rate
43) 88; this blood is redistributed from the brain, kidney, and GI mostly. See Figure 25.7 in the chapter.
44) sweating, increased cutaneous blood flow
45) E
46) A
47) Exercise hyperventilation involves an increase in rate and depth of pulmonary ventilation. The result is an increase in alveolar ventilation in proportion to the level of exercise.
48) oxygen, measured in liters of oxygen consumed per minute
Oxygen is required for aerobic ATP production, and ATP provides the energy for metabolism.
49) As Dmitri continued to exercise, his body became more used to the demands being placed upon it and increased the number of mitochondria. The increase in mitochondria make it possible to more efficiently use oxygen to make ATP which increases his endurance.
50) Potassium exits nerve and muscle cells with each action potential. Action potential rates increase in skeletal motor neurons, and in skeletal and cardiac muscle cells during exercise.
51) Exercise lowers the risk of cardiovascular disease, by lowering blood pressure, decreasing plasma triglycerides, and raising plasma HDLs. Exercise can partly reverse type 2 diabetes mellitus, by up-regulating glucose transporters and insulin receptors in skeletal muscle. Moderate, but not strenuous, exercise enhances the immune system. Exercise is inversely correlated with psychological depression.
52) Pulmonary ventilation rate increases immediately with onset of exercise, due to feedforward responses that originate with muscle and joint proprioceptors. These receptors send signals to the motor cortex, which affects the respiratory control center. The cardiovascular control center is also affected, resulting in generalized sympathetic discharge, which causes widespread vasoconstriction, increasing systemic blood pressure. Other effects include increased cardiac output and vasodilation in vessels of skeletal muscle to increase blood flow.
53) Benefits include decreased systemic blood pressure and resting heart rate, decreased plasma triglycerides, and increased plasma HDLs.
54) An advantage to glycolytic metabolism is that it is anaerobic; that is, ATP production can continue in the absence of oxygen. Another advantage is that ATP production by this method is very rapid. Disadvantages include low ATP yield per molecule of glucose and metabolic acidosis from buildup of lactate.
55) There are several theories. See "The Baroreceptor Reflex Adjusts to Exercise" section of the chapter.
56) When a skeletal muscle becomes more active, it has an increased demand for nutrients such as oxygen and glucose and quickly removes these from the surrounding interstitial fluid. This leaves fewer nutrients available for other cells that share the same interstitial fluid, such as the smooth muscle cells of the precapillary sphincter. As the available nutrients decline, energy production in the precapillary sphincters cannot keep pace with the need to keep the muscle in a contracted state, and the sphincters begin to relax. As they relax, the opening to the capillary becomes larger so that more blood flows into the capillary network that serves the skeletal muscle.
57) These individuals cannot rely on glycogen stores during exercise. Therefore, carbohydrates are available to them through only two pathways: gluconeogenesis and glucose from the diet. As a result, they must rely mostly on fat β-oxidation for energy.
58) Normally, only 20-25% of energy released during metabolism is converted to ATP. With hyperthyroidism, the oxidative phosphorylation is uncoupled, resulting in increased heat production. Therefore, this individual will be less efficient in ATP production. (Energy released during metabolism = Heat + ATP production). See the "25.5 Temperature Regulation During Exercise" section of the chapter. For information on hyperthyroidism, refer to Chapter 23.
59) People who exercise moderately have better immune systems than sedentary. However, people who exercise strenuously experience a decrease in immune function. Athletes in chronic energy deficit tend to be strenuous exercisers. In addition, cortisol suppresses the immune system (Chapter 23). Therefore, due to the elevated cortisol levels and the exercise stress, these individuals would likely exhibit a suppressed immune response.
60) Increased metabolic demands of skeletal muscle require increased blood flow, which is accomplished through vasodilation. Given the relatively large amount of skeletal muscle in the body, this widespread vasodilation is expected to produce a decrease in systemic blood pressure. Cardiac output increases through an increase in heart rate and stroke volume, which is expected to produce an increase in systemic blood pressure. What actually happens is a slight increase in systemic blood pressure. Part of the predicted decrease from vasodilation is offset by the fact that many other vessels constrict to redistribute blood flow to the dilated vessels. Total peripheral resistance, however, does decrease; the expected decrease in systemic blood pressure is offset by the increase in blood pressure resulting from increased cardiac output. The slight increase seen in systemic blood pressure that actually occurs during exercise indicates a loss of the normal baroreceptor reflex. The reasons for this are not understood, but may involve a change in baroreceptor threshold, presynaptic inhibition of baroreceptor afferent neurons, or influence of an unidentified muscle chemoreceptor.
61) CO = HR × SV. CO = 80 beats/min × 50 mL/beat = 4000 mL/min at rest. During exercise: 100 beats/min × 55 mL/beat = 5500 mL/min.
Overstretching of the heart muscle during venous return could damage it; thus a relatively higher heart rate is a safer w increase cardiac output.
62) Dancing is a type of athletic activity, a form of exercise that can be very challenging to the body. As she practices, she burns a lot of calories. If she is not replacing them with a balanced diet and enough calories, she will not have the fat stores she needs to do anaerobic respiration. If she continues to limit the fat in her diet to almost none, it will be hard for her to build up the necessary fat stores to make energy through β-oxidation of fats, decreasing her endurance and making her weak. Her body may even break down muscle in order to perform gluconeogenesis, causing her to lose strength. In addition, the lack of fat in her diet will make it difficult to absorb enough vitamin K, which will make it harder for her to clot-causing the bruising noticed by the physician and trainer. The lack of electrolytes in her diet may make her nerves and muscles become deficient in calcium and potassium, and they may not function properly. Finally, if she is undergoing catabolic breakdown of her muscle, that would increase the osmolarity of her cells and interstitial fluid, drawing more fluid from the blood and dropping blood pressure, making it more likely that she could develop orthostatic hypotension.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Gametes are produced by
A) sex chromosomes.
B) external genitalia.
C) autosomes.
D) internal genitalia.
E) gonads.
2) Egg and sperm cells have
A) 46 chromosomes.
B) 22 pairs of autosomes plus one pair of sex chromosomes.
C) 46 chromosomes, 23 chromosomes, and 22 pairs of autosomes plus one pair of sex chromosomes.
D) 23 chromosomes.
E) 46 chromosomes and 23 chromosomes. 2)
3) A zygote with the genotype YO will A) die.
B) have Turner's syndrome.
C) have Kleinfelter's syndrome.
D) develop into a female.
E) develop into a male.
4) A zygote with the genotype XO will
A) die.
B) have Turner's syndrome.
C) develop into a female and have Turner's syndrome.
D) develop into a male.
E) develop into a female.
5) X-linked genes are expressed
A) at equal rates in the two genders.
B) more often in males.
C) more often in females. 5)
6) The product of the SRY gene is
A) testis-determining factor.
B) anti-Müllerian hormone.
C) 5-α reductase.
D) dihydrotestosterone.
E) testosterone.
7) Bipotential gonads develop into testes under the influence of
A) peptide or protein hormones. B) estrogens.
C) androgens.
D) None of the answers are correct. 7)
8) When allowed to develop, the Müllerian ducts become the
A) penis and scrotum.
B) Fallopian tubes, uterus, cervix, upper vagina, distal vagina, clitoris, and labia.
C) Fallopian tubes, uterus, cervix, and upper vagina.
D) epididymis, vas deferens, and seminal vesicles.
E) distal vagina, clitoris, and labia.
9) Sister chromatids
A) are found in cells called primary gametes, contain twice the normal amount of DNA, and occur during ovum formation.
B) contain twice the normal amount of DNA.
C) occur during ovum formation.
D) are found in cells called primary gametes and contain twice the normal amount of DNA.
E) are found in cells called primary gametes.
10) At which stage of gametogenesis does gamete chromosome number reduce from 4N to 2N?
A) prior to the first meiotic division
C) prior to the first mitotic division
11) Mitotic divisions in germ cells
A) are complete before birth.
B) end at andropause or menopause.
C) continue throughout life.
D) begin at puberty.
E) The answer depends on gender.
12) Meiosis of one cell results in production of
A) four gametes if female, one if male.
C) one gamete.
B) during the second meiotic division
D) during the first meiotic division
B) four gametes if male, one if female.
D) four gametes. 12)
13) The enzyme responsible for converting androgens to estrogens is
A) AMH. B) TDF.
C) aromatase. D) 5α-reductase. 13)
14) To avoid down-regulation of GnRH receptors, GnRH is secreted
A) in periodic pulses.
C) by the testes.
15) The fold of skin that covers the tip of the penis is the A) prepuce.
B) corpus spongiosum.
C) glans penis.
D) penile urethra.
E) corpora cavernosum.
B) by the anterior pituitary.
D) only under the influence of FSH. 14)
15)
16) The erectile tissue that immediately surrounds the urethra is the
A) membranous urethra.
B) penile urethra.
C) corpus spongiosum.
D) corpora cavernosum.
E) glans penis. 16)
17) In the condition known as cryptorchidism, the
A) foreskin has been surgically removed.
B) prostate gland is enlarged.
C) testes are surgically removed.
D) sperm cells are not produced.
E) testes fail to descend into the scrotum.
18) The small paired glands at the base of the penis that produce a lubricating secretion are the
A) bulbourethral glands.
B) prostate glands.
C) Bartholin's glands.
D) preputial glands.
E) seminal vesicles.
19) Sperm production occurs in the
A) ductus deferens.
B) epididymis.
C) seminiferous tubules.
D) rete testis.
E) seminal vesicles.
20) Interstitial cells produce
A) nutrients.
B) sperm.
C) androgen-binding protein.
D) androgens.
E) inhibin.
21) The structure that carries sperm from the epididymis to the urethra is the
A) ejaculatory duct.
B) ductus deferens.
C) seminal vesicle.
D) corpus cavernosum.
E) rete testis.
22) The role of the pituitary hormone FSH in males is to
A) influence sexual behaviors and sex drive.
B) develop and maintain secondary sex characteristics.
C) initiate sperm production in the testes.
D) stimulate the interstitial cells to produce testosterone.
E) stimulate the Sertoli cells to produce GnRH.
23) The cervix is
A) the neck of the uterus, the sensory tissue of the vagina, and homologous to the penis.
B) homologous to the penis only.
C) the sensory tissue of the vagina only.
D) the neck of the uterus only.
E) the neck of the uterus and homologous to the penis.
24) The structure that transports the ovum to the uterus is the
A) myometrium.
B) vagina.
C) infundibulum.
D) uterosacral ligament.
E) Fallopian tube.
25) The average length of the menstrual cycle is A) 14 days. B) 21 days. C) 35 days. D) 10 days. E) 28 days.
26) The surge in LH and FSH that occurs during the middle of the ovarian cycle triggers
A) follicle maturation.
B) ovulation.
C) menopause.
D) atresia.
E) menstruation.
27) decreases ovarian follicle sensitivity to FSH.
A) Estrogen
B) Progesterone
C) GnRH
D) Anti-Müllerian hormone
E) LH
28) The dominant hormone secreted by the corpus luteum during the luteal phase is
A) LH.
B) FSH.
C) estradiol.
D) progesterone.
E) estrogen.
29) Menstruation is triggered decreased levels of
A) relaxin.
B) human chorionic gonadotropin.
C) progesterone.
D) LH.
E) FSH.
30) Which occurs during days 7-14 of the menstrual cycle?
A) ovulation
C) secretory phase
B) menses
D) proliferative phase
31) Which occurs during days 14-28 of the menstrual cycle?
A) menses
C) ovulation
B) secretory phase
D) proliferative phase
32) Emission is defined as
A) movement of sperm out of the penis.
B) loss of erection following orgasm.
C) engorgement of the penis.
D) movement of sperm into the urethra.
E) failure to achieve ejaculation.
33) Which occurs during an erection?
A) Vasoconstriction of penile arterioles.
B) Decreased nitric oxide.
C) The sympathetic nervous system constricts the veins leaving the penis.
D) The parasympathetic nervous system dilates the arteries going into the penis.
34) Which form of contraception allows fertilization but prevents implantation?
A) IUD
B) assisted reproductive technology
C) diaphragm
D) sponge
E) female condom
35) The corpus luteum in a nonpregnant woman usually lasts about A) 12 days. B) 3 months. C) 3 days. D) 28 days. E) 7 days.
36) Sperm cannot fertilize an egg until they
A) undergo decapitation.
B) lose their acrosome.
C) have been in the vagina for three days.
D) undergo capacitation.
E) undergo activation.
37) Polyspermy in humans results in
A) tetraploid adults.
B) individuals with haploid cells.
C) a nonfunctional zygote.
D) twins.
E) triplets. 37)
38) The embryo forms from the
A) outer layer of the blastocyst.
B) morula.
C) inner cell mass of the blastocyst.
D) zona pellucida.
E) placenta.
39) The chorionic villi
A) form the umbilical arteries.
B) form the umbilical cord.
C) increase the surface area available for exchange between the placenta and the maternal blood.
D) form the umbilical vein.
38)
E) form the portion of the placenta called the decidua capsularis. 39)
40) The hormone that is the basis for a pregnancy test is
A) progesterone.
B) relaxin.
C) human chorionic gonadotropin (hCG).
D) human placental lactogen (hPL).
E) LH.
41) Which hormone is NOT produced by the placenta?
A) luteinizing hormone
B) relaxin
C) human chorionic somatomammotropin (hCS)
D) human chorionic gonadotropin (hCG)
E) progesterone
42) During pregnancy, uterine contractions are inhibited by increased levels of
A) oxytocin.
B) prostaglandins.
C) estrogen.
D) progesterone.
E) All of the answers are correct.
43) The hormone mainly responsible for milk production is
A) growth hormone.
B) prolactin.
C) progesterone.
D) estrogen.
E) oxytocin.
44) The hormone mainly responsible for the milk let-down reflex is
A) estrogen.
B) oxytocin.
C) growth hormone.
D) progesterone.
E) prolactin.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the bipotential structure with its sex-specific result.
Match the ploidy with a cell stage
50) germ cell
51) spermatogonium or oogonium
52) mature sperm or egg
53) primary spermatocyte or oocyte
54) secondary spermatocyte or oocyte
Match the cells/tissue with the hormone it secretes.
55) progesterone, early in pregnancy
56) human chorionic gonadotropin (hCG)
57) estrogen, in the early follicular stage
58) testosterone
B) quadriploid (4N) C) haploid (1N)
interstitial (Leydig) cells
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
59) Which is the name for the male gonad?
A) ovaries
B) prostate gland
C) vas (ductus) deferens
D) seminal vesicle
E) testis
60) Which is the name of the eggs produced by the ovaries?
A) primordial follicle
B) ova
C) sperm
D) antrum
E) theca cells
61) What is the name of the process which produces sperm?
A) acrosomal reaction
B) capacitation
C) oogenesis
D) testogenesis
E) spermatogenesis
62) Which structure is the source of sperm?
A) bulbourethral glands
B) prostate glands
C) seminal vesicle
D) seminiferous tubules
E) epididymis
63) In order to produce spermatids, a primary spermatocyte undergoes divisions. A) one B) two C) three D) four E) five
64) During ovulation, an oocyte released out of a
A) primary follicle.
B) tertiary follicle.
C) corpus luteum.
D) dominant follicle.
E) secondary follicle.
65) Mucus functions as a lubricant in the semen. Which structure produces mucus?
A) seminiferous tubules
B) bulbourethral glands
C) prostate gland
D) seminal vesicle
E) epididymis
66) Which is responsible for the development of the Wolffian duct into the epididymis, vas deferens, and seminal vesicle?
A) estrogen
B) testosterone
C) anti-Müllerian hormone
D) testis determining SRY protein
E) progesterone
67) When the testis does not produce anti-Müllerian hormone, the Müllerian ducts develop into the
A) vagina.
B) ovaries.
C) vas deferens.
D) epididymis.
E) seminiferous tubules.
68) Which drives female libido?
A) gonadotropin releasing hormone
B) estrogen
C) adrenal androgens
D) progesterone
E) lutenizing hormone 68)
69) Which hormone inhibits FSH secretion in the male?
A) testis-determining factor
B) testosterone
C) lutenizing hormone
D) dihydrotestosterone
E) inhibin
70) , produced by ovarian follicles during the first part of the ovarian cycle, prevents too many follicles from developing at one time.
A) Estrogen
B) Lutenizing hormone
C) Gonadotropin releasing hormone
D) Follicle stimulating hormone
E) Anti-Müllerian hormone
71) Erectile dysfunction can be an early indicator of
A) hypotension.
B) pulmonary edema.
C) multiple sclerosis.
D) kidney failure.
E) atherosclerosis.
72) Which occurs during the excitement phase in the female during the human sexual response?
A) orgasm
B) ejaculation
C) coitus
D) vaginal lubrication
E) emission
73) During pregnancy, contributes to the development of the milk-secreting ducts of the breast.
A) human chorionic gonadotropin (hCG)
B) oxytocin
C) estrogen
D) progesterone
E) gonadotropin releasing hormone (GnRH) 73)
74) Place the events of fertilization and implantation in order.
1. Implantation of the developing embryo.
2. The developing embryo becomes a blastocyst which consists of a hollow ball of cells.
3. Mitosis occurs in the Fallopian tube.
4. The cortical reaction occurs, preventing polyspermy.
5. The egg is fertilized by the sperm.
A) 5, 4, 3, 2, 1 B) 4, 5, 2, 3, 1 C) 5, 3, 4, 1, 2 D) 5, 3, 2, 4, 1 E) 4, 3, 5, 2, 1
75) cells produce testosterone while cells regulate sperm development.
A) Epididymal, prostate
B) Follicular, interstitial
C) Sertoli, interstitial
D) Interstitial, epididymal
E) Interstitial, Sertoli
74)
75)
76) Which hormone may be responsible for loosening pelvic bone ligaments prior to birth?
A) relaxin
B) inhibin
C) corticotropin releasing hormone (CRH)
D) oxytocin
E) progesterone
77) Which is a function of human chorionic somatomammotropin (hCS)?
A) It is the primary signal for the release of breast milk.
B) It stimulates contraction of the smooth muscle in the uterus during birth.
C) It maintains the corpus luteum after fertilization.
D) It alters mother's glucose and fatty acid metabolism.
E) It loosens the ligaments in the pelvic bone before birth.
78) Which does NOT occur during labor?
A) Prostaglandins produced in the uterus.
B) Stretch occurs in the cervix.
C) Oxytocin released from the anterior pituitary.
D) Fetus drops lower in the uterus.
E) Uterine contractions occur.
79) Which is responsible for the cessation of reproductive cycles in women?
A) The ovaries produce more estrogen.
B) The ovaries are unable to respond to lutenizing hormone or follicle stimulating hormone.
C) The anterior pituitary no longer produces lutenizing hormone.
D) The hypothalamus no longer produces gonadotropin releasing hormone.
E) The ovaries no longer produce progesterone.
80) Which hormone contributes to the onset of puberty?
A) leptin
B) oxytocin
C) testosterone
D) relaxin
E) corticotropic releasing hormone
81) Which is responsible for sweeping the ovulated egg toward the Fallopian tube and away from the abdominal cavity?
A) cervix
B) myometrium
C) fimbriae
D) ovary
E) uterus
82) Which is NOT a part of the ovarian cycle?
A) corpus luteum formation
B) menses
C) ovulation
D) luteal phase
E) follicular phase
83) Which hormone is used as in indicator of polycystic ovary syndrome?
A) estrogen
B) follicle stimulating hormone (FSH)
C) lutenizing hormone (LH)
D) anti-Müllerian hormone (AMH)
E) progesterone
84) Identify the FALSE statement.
A) Estrogens control the development of the reproductive organs in the female fetus.
B) Meiosis is never completed in most oocytes.
C) Androgens control the development of reproductive organs in the male fetus.
D) Females have one less active chromosome than males.
E) Gametogenesis begins in the female fetus.
85) The following is a list of structures of the male reproductive tract.
1. vas deferens
2. urethra
3. ejaculatory duct
4. epididymis
Identify the order in which sperm pass through these structures from the testes to the penis.
A) 1, 3, 4, 2 B) 4, 3, 1, 2 C) 4, 1, 3, 2
86) In the follicular phase of the ovarian cycle, the ovary is
A) secreting progesterone.
B) forming a corpus luteum.
C) releasing a mature egg.
D) undergoing atresia.
E) maturing a follicle.
87) An embryo with a genital tubercle, urethral folds, and urethral groove must be
A) under six weeks old.
C) seven weeks old.
86)
87)
B) nine weeks old.
D) Unable to determine the age.
88) Hemophilia, color blindness, and Duchenne muscular dystrophy occur more often in males than females. Why?
A) Testis-determining factor (TDF) causes these conditions.
B) The Y chromosome has been deactivated in males with these conditions.
C) These traits are carried only on the Y chromosome.
D) These conditions develop due to the lack of estrogen and progesterone.
E) These traits are carried on the X chromosome, and since there is no matching gene on the Y chromosome, the traits are expressed more often in males.
89) In the late follicular phase of the ovarian cycle, the level of LH secretion is the level of FSH secretion.
A) less than B) greater than C) equal to
90) For the early to mid-luteal phase of the ovarian cycle, the level of progesterone is the level of estrogen.
A) equal to
B) less than C) greater than
88)
89)
90)
91) A boy male who has not passed through puberty sustains has an injury to his anterior pituitary such that which stops FSH is no longer released, but LH is normal. After the individual grows to maturity, one would expect that he would likely
A) have impaired function of the interstitial cells.
B) not develop secondary sex characteristics.
C) be sterile.
D) be impotent.
E) produce large amounts of inhibin.
92) A male body builder starts taking injections of testosterone (an anabolic steroid) daily. After three weeks, which would you expect?
A) decreased GnRH
B) increased sex drive
C) decreased FSH
D) decreased LH
E) All of the above. 92)
93) If the ovaries were removed from a 20-year-old female, which would you expect?
A) increased FSH
B) increased GnRH
C) cessation of menstruation
D) increased LH
E) All of these observations
94) If adenylyl cyclase (the enzyme that converts ATP to cAMP) is blocked,
A) the mammary glands would not respond to progesterone.
B) the corpus luteum would not respond to hCG.
C) endometrial cells would not respond to estradiol.
D) the activity of progesterone at the endometrium would increase.
E) the level of progesterone produced by the ovary during the luteal phase would increase. 94)
95) A vasectomy prevents which of the following?
A) ejaculation
B) spermatogenesis
C) formed sperm from entering ejaculate
D) erection
E) ejaculation and spermatogenesis
96) Zahra jogs many miles every day. She has lost weight so that she is now underweight for her height and has very little fat tissue. You would expect Zahra to have
A) double ovulation.
B) amenorrhea.
C) painful menstrual cramps.
D) increased FSH.
E) heavy menstrual flows. 96)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
97) Sperm cannot fertilize an egg unless they have been in the female reproductive tract for several hours. This increased ability of the sperm to fertilize the ovum is called capacitation. Laboratory studies show that sperm can be capacitated artificially if they are first washed in a saline solution containing human plasma. Based on this information, think about some possible changes that occur to sperm during capacitation, and suggest some possible factors involved in these changes.
98) List the parts of the uterus, including the layers of the wall. Briefly explain the function of each.
99) List and briefly explain the function of each portion of the male reproductive tract, in order, from where the sperm cells are first produced to where they leave the male's body.
100) List the three accessory glands and ducts of the male reproductive system and describe their function.
101) In males, which cells are the main targets for FSH? What effect does the hormone have on these cells?
102) In males, which cells are the main targets for LH? What effect does the hormone have on these cells?
103) It has been reported that King Henry VIII of England divorced his wives because they were unable to produce a male heir to the throne. Some say the lack of a male heir is also used as a reason for marrying additional wives in polygamous societies. From a genetics standpoint, what is wrong with these assumptions?
104) Explain how modern birth control pills work as contraceptives.
105) What seems to be the most likely hormone that we could use as a male contraceptive pill? Explain.
106) List the male and female structures that develop from the following bipotential structures: genital tubercle, urethral folds and grooves, labioscrotal swellings, gonadal cortex, gonadal medulla, Wolffian duct, Müllerian duct.
107) List and discuss three to five different methods of contraception, including at least one barrier method and one hormonal treatment.
108) Why is the scrotum, the sac that contains the testes, located outside of the body?
109) Create a diagram explaining the feedback of estrogen on the anterior pituitary during the ovarian cycle.
110) In some cultures, infant boys are circumcised. Explain what circumcision is and why there is support for as well as opposition to the procedure.
111) Mrs. Becker is trying to become pregnant. One of the Beckers' favorite ways of relaxation is to soak in the hot tub while drinking wine. A year has gone by with no pregnancy occurring, so they visit your clinic. You conclude that the hot tub is a possible factor in Mr. Becker's infertility. Angered and insulted, both assure you that they have no difficulty having intercourse, unless Mr. Becker has had too much wine, which happens infrequently. How will you explain to them the difference between impotence and infertility? Why should you suspect the hot tub as a factor in Mr. Becker's lowered sperm count? Is the wine a factor as well?
112) Biruk is in an automobile accident that cuts his spinal cord at waist level. After his recovery, he wonders if he will still be able to have an erection, enjoy sex, and father a child. What would you tell him?
113) In a condition known as endometriosis, endometrial cells are present in the uterine tubes and/or in the peritoneal cavity where they become established tissues. A major symptom of endometriosis is periodic pain. Why do you think this occurs?
114) Oral contraceptive pills containing estradiol or estradiol plus progesterone are given at specific doses during the ovarian cycle to prevent follicle maturation and ovulation. Explain how these pills work.
115) Explain what might happen to sexual function in a male taking sympathetic nervous system inhibitors to treat his hypertension.
116) Explain why observations of basal body temperature are useful for couples who want to get pregnant, but are only of limited use for couples who are trying to avoid getting pregnant.
117) Hormone replacement therapy can be used to treat symptoms of menopause. Typically, estrogen and progesterone are used rather than GnRH, FSH, and LH. Why?
118) The youngest female documented to have given birth to a healthy child was a 5-year-old girl in the 1930s; the father was never identified. She began having regular menstrual periods around eight months of age. She was diagnosed as pregnant after being taken to a doctor for suspicion of having an abdominal tumor; her periods had stopped several months earlier and her breasts were well-developed. When do the reproductive organs normally develop? Describe the maturation her body underwent to make her fertile, specifying at what ages these changes normally take place. Even without a positive pregnancy test, what clues suggest pregnancy rather than a tumor? What is the earliest age at which gamete development normally begins and ends in both genders?
119) Hydatidiform mole is a type of pregnancy that, without medical intervention, frequently results in the death of the mother. The hydatidiform mole is thought to result most often from an abnormality in fertilization, such that the egg has two copies of paternal chromosomes, and no maternal DNA. A fetus fails to develop; instead there is rapidly growing chorionic tissue in the placenta, which secretes hCG and thus leads to a positive pregnancy te and outward signs of pregnancy. The first clue to the obstetrician that the pregnancy is abnormal is often the lack heartbeat in the first trimester.
A. What is the genotype of the hydatidiform mole tissue? From the genotype alone, would most science-literate students predict that a normal embryo would form? Explain, indicating what this suggests about maternal and p contributions to the embryo.
B. The most common cause of molar pregnancy-related maternal death is a type of cancer called choriocarcinom the hydatidiform mole being the source and thus resembling a tumor. What characteristic of tumors leads to can C. While these pregnancies often spontaneously abort, some women may elect to terminate a hydatidiform mola pregnancy. Is this a special case of elective abortion or is it tumor-removal? Explain.
120) Which characteristics determine gender (consider genetic, anatomical, hormonal, and other factors)? Is it always the case that genetic, psychological, and physical gender cues indicate the same gender? Explain your answer, citing specific examples of conditions in which gender does not match sex.
121) Describe the events that must occur in order for sperm to penetrate an egg. What prevents more than one sperm from entering? In the case of twins, how many sperm entered the egg? Why must a man have millions of sperm in a semen sample to be considered fertile? If only one sperm were present in the semen and that sperm managed to find its way to the egg, could it fertilize the egg? Explain.
122) Describe the development of reproductive organs in a fetus of each sex. Which genes, gene products, and hormones are involved in the sex differences? Which sex-related hormones are circulating in high concentrations in a pregnant woman compared to a nonpregnant woman? Do these hormones cross the placenta (if you are uncertain, consider hormone chemical class relative to membrane permeability to make an educated guess)? Assuming these hormones do cross the placenta, how do they affect the hormonal environment inside the fetus, and how does this relate to fetal reproductive development?
123) Create a flow chart illustrating the development of bipotential reproductive structures in an XY individual and a individual, indicating the stimuli for development or regression of the structures. Add to this chart the changes t occur at puberty and their stimuli. Finally, show the points on the chart at which abnormalities associated with t following conditions occur:
A. testicular feminization or androgen insensitivity (XY genotype, permanent female external morphology with testes and androgen production but faulty androgen receptors);
B. male pseudohermaphrodites (XY genotype and external female morphology with internal testes, and masculi occurring at puberty);
C. congenital adrenal hyperplasia (XX genotype with normal female internal organs, masculinized external orga observed at birth);
D. sexual development is similar in nonhuman mammals, but there are some interesting pathologies not seen in humans. A freemartin occurs in cattle twins, with one male and one female. The male is normal but the XX fema sterile, born masculinized, and has testicular tissue. Explain the most likely cause of this masculinized phenotyp indicate on your chart the point or points at which something abnormal occurred.
124) Endocrine disruptors are environmental chemicals, which, if people and other animals are exposed, can have hormone-mimicking or hormone-blocking effects. These chemicals are used in industries and in homes and are associated with such commonly-used products such as pesticides and herbicides, plastic food containers, and baby bottles. Those that mimic or block sex steroids are of special concern, because they are present in household plastics and are fat-soluble, thus easily stored in fatty tissue of the body and can affect a developing f Research is ongoing and results are controversial, but these chemicals have been associated with:
A. delayed sexual maturity in fish;
B. poor masculinization of genitals in male alligators with decreased ability to produce offspring;
C. feminized behavior in male rats, and in humans;
D. decreased lactation;
E. diminished male genitals and semen quality; and F. early puberty.
For each condition A-F, specify which hormones may have been blocked or mimicked. (Endocrine regulation in fish, alligators, and rats is nearly identical to that in humans.)
Answer Key
Testname: UNTITLED47
1) E
2) D
3) A
4) C
5) B
6) A
7) D
8) C
9) D
10) D
11) E
12) B
13) C
14) A 15) A
16) C
17) E
18) A
19) C
20) D
21) B
22) C
23) D
24) E
25) E
26) B
27) D
28) D
29) C
30) D
31) B
32) D
33) D
34) A
35) A
36) D
37) C
38) C
39) C
40) C
41) A
42) D
43) B
44) B
45) A
46) D
47) E
48) C
49) B
50) A
Answer Key
Testname: UNTITLED47
51) A
52) C
53) B
54) A
55) B
56) A
57) C
58) D
59) E
60) B
61) E
62) D
63) B
64) D
65) B
66) B
67) A
68) C
69) E
70) E
71) E
72) D
73) C
74) A
75) E
76) A
77) D
78) C
79) B
80) A
81) C
82) B
83) D
84) A
85) C
86) E
87) A
88) E
89) B
90) C
91) C
92) E
93) E
94) B
95) C
96) B
97) Capacitation involves physiological changes in the sperm head membrane that allow it to successfully penetrate the membranes of the ovum. This process might involve the removal of some inhibiting substance(s) from the sperm. It might involve an immunological reaction with proteins or other components of the vaginal environment. This is an area of active research, and there are many potential factors involved in the process of capacitation.
98) The uterus consists of the cervix or neck, the body, and the oviducts or Fallopian tubes. The wall layers are an outer connective tissue, middle myometrium, and inner endometrium. See Figure 26.9 in the chapter.
99) Sperm originate in the walls of the seminiferous tubules, which compose the bulk of the testes. The sperm mature in the epididymis, a coiled tubular structure on the surface of the testis. Upon ejaculation, the sperm enter the vas (ductus) deferens, flow through the prostate gland in the ejaculatory duct, and then exit the body through the urethra, which is also how urine leaves the body.
100) The prostate gland, seminal vesicles, and bulbourethral (Cowper's) glands all provide the components of the semen other than the sperm (i.e., fructose, mucus, etc.).
101) Sertoli cells; FSH stimulates synthesis of paracrine factors that activate spermatogenesis in germ cells. FSH also stimulates the production of androgen-binding protein and inhibin.
102) Interstitial (Leydig) cells; LH stimulates these cells to produce testosterone.
103) Only males can contribute the Y chromosome, so the father determines the gender of the offspring.
104) Birth control pills contain hormones such as estrogen and progesterone that act through negative feedback to inhibit the release of GnRH, which in turn prevents release of FSH and LH. Thus, primordial follicles do not develop and ovulation is prevented.
105) GnRH agonists would decrease the secretion of GnRH thus decreasing the level of the gonadotropins, FSH and LH, and therefore allowing the testes to stop producing sperm.
106) See Figure 26.2 in the chapter.
107) Barrier methods include diaphragms, cervical caps, contraceptive sponges, and condoms. Barriers prevent the sperm from reaching the egg. Hormonal methods include pills containing estrogen and progesterone, which prevent ovulation.
108) Optimum conditions for sperm development require that sperm be kept at 2 to 3 degrees below body temperature.
109) During early/mid follicular phase, low levels of estrogen inhibit FSH and LH release from the anterior pituitary. In late follicular phase, rising levels of estrogen stimulate the release of FSH and LH. High levels of estrogen, however, along with progesterone in the luteal phase negatively feed back to the anterior pituitary preventing further release of FSH and LH.
110) Circumcision is removal of the foreskin of the penis. Supporters of the procedure believe it may reduce chances of acquiring and/or possibly infecting a partner with certain diseases, including urinary tract infections, sexually transmitted diseases, and penile cancer. Opponents suggest the incidence of these is too low to warrant inflicting pain and mutilating the infant, and possibly decreasing sexual pleasure when the child becomes an adult.
111) Impotence is the inability to sustain an erection; infertility in this instance is due to the inability to produce mature gametes. These are totally separate events. In this case, the elevated temperature of the hot tub may cause sperm cell production to decline or sperm maturation to cease. Alcohol can inhibit sexual performance; however, a small amount can enhance performance by decreasing inhibition.
112) Yes, he would still be able to have an erection, though he would lack the pleasurable sensations that normally accompany erection. Erection is controlled primarily by a parasympathetic reflex originating in the sacral region of the spinal cord (inferior to the injury). Tactile stimulation of the penis would initiate the parasympathetic reflex that controls erection. Biruk would also be able to experience an erection by a sympathetic route, since this would be controlled in the T12 to L2 area of the cord (superior to the injury). Stimulation by higher centers could produce a decreased sympathetic tone in the vessels to the penis resulting in an erection. His injury should have no effect on sperm production and ejaculation should still be possible, so he should be able to father a child.
113) The endometrial cells have receptors for the hormones estrogen and progesterone and respond to these hormones the same as they would if they were in the body of the uterus. Under the influence of estrogen, they proliferate at the beginning of the menstrual cycle and begin to develop glands and blood vessels, which then further develop under the control of progesterone. This dramatic change in tissue size and characteristics interferes with neighboring tissues by pressing on them or interrupting function in other ways. It is this interference that causes the periodic painful sensations.
114) Slightly increased levels of estradiol or estradiol and progesterone inhibit both GnRH at the hypothalamus and the release of FSH and LH from the pituitary. Without FSH, primordial follicles do not initiate development, and the endogenous levels of estrogen remain low. An LH surge is necessary for ovulation to occur, and the LH surge is triggered by the peaking of estradiol. If the level of estradiol is not allowed to rise above the critical level, the LH surge will not occur and ovulation will not occur, even if a follicle managed to develop to a stage at which it could ovulate. Any mature follicles would ultimately degenerate, and no new follicles would mature to take their place. Although the ovarian cycle is interrupted, the level of hormones is still adequate to regulate a normal menstrual cycle.
115) The male could potentially suffer from a form of sexual dysfunction that prevents ejaculation. Recall from Chapter 11, the sympathetic division of the autonomic nervous system is responsible for penile ejaculation whereas the parasympathetic division is responsible for penile erection.
116) The hormone progesterone is released after ovulation and is associated with a rise in body temperature. The slight rise in body temperature is evidence that a woman has already ovulated, and the elevation remains until the beginning of the next menstrual cycle. Couples who are trying to avoid getting pregnant cannot use the lower temperature as an indication that ovulation has not occurred because the temperature elevation is not immediate, and furthermore they must understand that sperm survive for several days in the female reproductive tract.
117) At menopause, the ovaries no longer respond to GnRH, FSH, or LH. Since these hormones are no longer available, direct regulation of estrogen and progesterone can be achieved through supplemental hormones.
118) Internal reproductive organs are present as early as six weeks after fertilization. The reproductive organs are gender-distinct by 10 weeks. To be fertile means to have mature reproductive organs and active hormonal control of a menstrual cycle. Final sexual maturation resumes at puberty as hormone production increases, normally between ages 8 and 14. These changes include the onset of menses, breast growth, skeletal changes, and development of axillary and pubic hair. The presence of breasts and history of menstrual cycling were major clues for suspecting pregnancy. Gamete development begins in fetuses of both genders with mitotic divisions in germ cells. Meiosis begins in female fetuses but halts in meiosis I, resuming at puberty and halting in meiosis II, and finishing meiosis only if fertilization occurs. Meiosis begins and is completed in males starting at puberty.
119) A. The genotype would be 46XX or 46XY; 46YY is not viable at all because the essential genes on the X chromosome are missing. These genotypes are normal, so it is unclear why a fetus does not form. This suggests that there is some contrib the maternal nucleus to development apart from just the chromosome number.
B. It is metastasis, or spread of abnormal cells due to loss of cell adhesion, that causes cancer.
C. Answers are based in part on personal opinion and will vary; if students consider primarily that this pregnancy does produce a fetus at all, they may argue that removal of this tissue is more like tumor removal than aborting a fetus.
120) Gender is determined by sex chromosomes, by internal and external genitals, by sex hormones, and by psychological factors. Pseudohermaphrodites are XY with male internal genitals, but are deficient in one of the male hormones that trigger formation of external genitals. Thus, they are born looking like girls. At puberty, however, more male characteristics begin to develop. Testicular-feminized males lack androgen receptors so their testes fail to descend and their brains are not masculinized, and their outward appearance is female, though they are sterile. Adrenal tumors can secrete hormones that masculinize or feminize the opposite genetic sex. Sometimes psychological gender identity fails to match genetic sex, for unknown reasons.
121) The sperm must penetrate the corona radiata and the zona pellucida, which surround the egg, in order to get to its membrane. The acrosome of the sperm contains enzymes that disrupt these barriers. The first sperm to reach the membrane binds to a receptor, the sperm and egg membranes fuse, and the sperm nucleus enters the egg. The cortical reaction ensues, in which granules in the egg spill their contents out of the membrane, which alters it in a way preventing additional sperm from binding. Twins result from normal fertilization, but either two eggs are present or the early embryo splits. Only about 100 sperm manage to find the egg, with the other millions swimming off in the wrong direction. One sperm probably does not contain enough enzymes to allow penetration of the egg barriers.
122) Each fetus initially has the same bipotential structures. These become distinct testes or ovaries and the internal and external genitals typical of each sex by 10 weeks. In males, the change in bipotential structures begins with expression of the SRY gene on the Y chromosome, which produces testis-determining factor. Once the testes develop, they secrete androgens and anti-Müllerian hormone, which completes the masculinization of the fetus. The female structures develop in the absence of SRY and consequent hormones. Maternal estrogen and progesterone are very high, and as steroids they easily cross the placenta, creating a very female hormonal environment in a fetus of either gender. This underscores the importance of the male hormones in masculinizing male fetuses.
123) Chart of normal male development should resemble Figures 26.2 and 26.3 in the chapter, with a similar chart in parallel female development. Appearance of secondary sexual characteristics in both biological sexes results from increases in g steroids and adrenal androgens.
A-B. Both testicular feminization and male pseudohermaphroditism begin with lack of response of target tissues to and produced in fetal development; testicular feminization allows development of female secondary sexual characteristics, pseudohermaphroditism allows masculinization at puberty.
C. Congenital adrenal hyperplasia allows normal development of female internal structures, but masculinizes external before birth as an effect of adrenal androgens. If untreated, puberty-related changes would also be masculine.
D. The freemartin cow must receive anti-Müllerian hormone through shared placental circulation; therefore testicular tissue develops and androgens are secreted to produce further masculinization, in the fetus and at puberty.
124) A. blocked estrogen and androgen;
B. blocked testosterone or mimicked estrogen;
C. blocked testosterone or mimicked estrogen;
D. blocked estrogen or prolactin;
E. blocked testosterone; and
F. mimicked estrogen.