BIOD 151 Module 3 Complete Solutions

BIOD 151 Module 3 Two divisions of the digestive system - ✔alimentary canal and accessory organs seven parts of the gastrointestinal tract - ✔mouth, pharynx, esophagus, stomach, small intestine, large intestine and anus six digestive accessory organs - ✔teeth, tongue, gallbladder, salivary glands, liver, pancreas mouth opening - ✔lips floor of the mouth - ✔tongue walls of the mouth - ✔cheeks roof of mouth - ✔hard and soft palates two bones and membrane the tongue is attached to - ✔hyoid and mandible bone and membranous lingual frenulum How many teeth are in the human adult and what do they do? - ✔thirty-two teeth work together to tear, crush and grind food to mechanically digest food.

What are the four types of teeth? - ✔incisors, canines, premolars, molars incisors - ✔two, chisel shaped for biting canine - ✔one pointed for tearing pre-molars - ✔two fairly flat for grinding molars - ✔three flat for crushing What is the specific function of the salivary gland in the process of digestion? - ✔Food is mixed and moistened with the saliva secreted from the salivary glands that contain enzymes that begin chemical digestion process by breaking down starch.

Where are the taste buds located? - ✔Primarily the tongue but also the surface of the mouth and wall of the pharynx.

Describe the function of the tongue in the digestive process - ✔tongue grips the food, constantly repositioning it between the teeth and forms the bolus that is pushed back to the pharynx to be swallowed. bolus - ✔compact mass of food formed by chewing of the teeth and reposition by the tongue. three parts of the pharynx - ✔nasopharynx, oropharynx, laryngopharynx through which sections of the pharynx does air travel? food? - ✔air travels through all three sections food travels through oropharynx and laryngopharynx What prevents food from entering the lungs and why is this necessary? - ✔The epiglottis covers the esophagus and prevent aspiration of food and liquid.

Describe how the muscular layers in the pharynx assist with food passage. - ✔The two layers of muscle, circumferential outer layer and inner longitudinal layer, alternatively contract to squeeze the food into the esophagus by peristalsis.

Tissue layers of the esophagus - ✔the innermost layer is the mucosa which secretes mucus into the interior the gastrointestinal tract, the second layer is the submucosa which contains blood and lymph vessels, lymph nodes, nerves, and mucous glands, the third layer is the muscularis externa which is made of two layers of muscle: the outer longitudinal fibers and inner circumferential fibers and the outermost layer is the serosa which is made up of cells that make serous fluid.

Peristalsis - ✔the squeezing of food through the GI tract by the alternating contraction of the sets of longitudinal and circumferential muscles. three main divisions of the tooth - ✔crown, neck, root three types of papillae - ✔filiform, fungiform, circumvallate Which papillae contain taste buds - ✔Circumvallate and fungiform Describe the shape of the stomach and its location relative to the abdomen and diaphragm. - ✔stomach is a backward C-shaped organ located along the left side of the abdomen and below the diaphragm Describe the passage of food into and out of the stomach - ✔Food enters from the esophagus via the cardioesophageal sphincter and exits the stomach via the pyloric sphincter into the small intestine

lesser curvature - ✔concave, extends inward on the shorter side of the stomach greater curvature - ✔convex, extends outward on the shorter side of the stomach lesser omentum - ✔serous membrane that attaches lesser curvature to the liver greater omentum - ✔serous membrane which attaches greater curvature to the posterior wall of the body two functions of the stomach - ✔1. Temporary storage area for food, storing up to two liters of partially digested food.

2. The muscular walls of the stomach contract vigorously and mix food with juices that are secreted when food enters the stomach, allowing food to be broken down into smaller pieces.

The pH of stomach is 1.3 - 3.5. What is this due to and what is its source and function? ✔It is due to hydrochloric acid secreted by parietal cells. High acidity level kills bacteria and converts inactive pepsinogen into active enzyme pepsin.

What is the source of the stomach enzyme pepsin and what is its function? - ✔Inactive pepsinogen secreted by chief cells and converted into active enzyme pepsin by HCI. Pepsin then begins breakdown of proteins.

What is a stomach ulcer? - ✔open sore on the stomach wall Explain in detail how the stomach contents enter the small intestine - ✔The pyloric sphincter valve, located at the base of the stomach, relaxes causing a small quantity of chyme to pass through the opening into the first part of the small intestine. This initiates a reflex that causes the muscles of the sphincter to contract and close the opening temporarily. Then the sphincter relaxes again and allows more chyme to enter.

Three sections of the small intestine - ✔duodenum, jejunum, ileum smallest section of small intestine - ✔duodenum What are the names of the valves which are located at the beginning and end of the small intestine? - ✔The pyloric sphincter is at the end of the stomach and ileocecal valve is at the large intestine.

List the three specialized structures in the wall of the small intestine. - ✔circular folds, villi, microvilli Where is bile formed and stored? - ✔formed in liver, stored in gallbladder

Describe the 2 major functions of pancreatic juice - ✔1. Contains sodium bicarbonate which neutralizes the chyme and makes the pH of the small intestine slightly basic.

2. Contains digestive enzymes that further digest every major component of food.

Describe how fats, sugars and amino acids are absorbed by the small intestine. ✔Sugars and amino acids enter villi cells and absorbed into the bloodstream. Glycerol and fatty acids enter villi cells and are reassembled into fat molecules, which move into lacteals.

What are the three functions of the liver that are important in digestion? - ✔1. produces bile, which emulsifies fat 2. stores glucose as glycogen and breaks down glycogen to glucose between meals to maintain constant glucose concentration in the blood.

3. produces urea from amino groups that are removed from excess amino acids eight regions of the large intestine - ✔1. Cecum 2. appendix 3. ascending colon 4. transverse colon 5. descending colon 6. sigmoid colon 7. rectum 8. anal canal Two sphincters of the anal canal - ✔an involuntary smooth muscle internal sphincter and voluntary skeletal muscle external sphincter 4 functions of large intestine - ✔1. propels waste 2. reabsorbs water 3.reabsorbs electrolytes 4. absorbs Vitamin K and certain B vitamins produces by intestinal bacteria What are the 2 major physiological problems caused by diarrhea? - ✔When materials pass through the colon too quickly, excess water is not reabsorbed, and diarrhea will result, which can lead to serious dehydration and electrolyte loss. contents of feces - ✔75% water, 25% solid matter containing intestinal bacteria, undigested plant material, fats, bile pigments, inorganic material, mucus, and dead intestinal cells Name 4 main functions of performed by the digestive system - ✔ingestion, digestion, absorption, defecation What digestive system functions are carried out by the mouth? - ✔Ingestion and digestion. explain which digestive system functions are carried out by the stomach - ✔Mechanical digestion continues as muscles churn and mix the food, breaking it into smaller intestine by peristalsis. Chemical digestion continues as pepsin digests proteins.

Explain which digestive system functions are carried out by the small intestine. ✔Chemical digestion continues as enzymes from the pancreatic juices break down starches and proteins, and begin digestion of fat. Mechanical digestion continues as bile breaks down fat into smaller pieces. Absorption begins as digested food molecules, water and fat are absorbed into the bloodstream.

Explain the two main hormones that are responsible for hunger and satiety. - ✔Leptin is produces by adipose tissue. It alerts the brain to turn off the hunger center in the brain and activate the satiety center when consuming a meal. Ghrelin is produced by the stomach and does the opposite. It travels to the brain and deactivates the satiety center.

Ideally, work together to balance.

5 biochemical materials needed by the body that are found in food - ✔Carbohydrates, proteins and lipids that are needed in large amounts. Vitamins and minerals are also needed in small amounts.

What are the two classes of carbohydrates and in what foods can each be found? ✔Starches and sugars. Milk and fruits such as apples or peaches contain sugar, while grains such as wheat and vegetables such as potatoes contain starches.

What are the three classes of lipids? - ✔Saturated fats, unsaturated fats and cholesterol What are the two classes of proteins and in what foods can each be found? - ✔Proteins can be categorized as complete or incomplete proteins. Examples of complete proteins are meat, poultry, eggs, milk or diary products, and soy beans. Examples of incomplete proteins are grains, legumes, seeds and nuts.

What is the definition of an essential amino acid and how many are there for adults and where can they be found? - ✔There are nine essential amino acids required in an adult diet. They are unable to be produced by the human body. Complete proteins contain all nine.

What are the two classes of vitamins? How is a vitamin different from carbs, lipids or proteins? Why can ingestion of excessive amounts of one type be dangerous. - ✔Two classes are water-soluble and fat-soluble. Vitamins are organic compounds that are not consumed in metabolic reactions but help enzymes carry them out to contribute nutrients to materials needed by the body. Fat-soluble vitamins can be stored in body fat and can be problematic if consumed in excess.

List 2 ways in which minerals are different than carbohydrates, lipids and proteins. List seven minerals needed in the human diet and four foods which are food sources. ✔Minerals are inorganic compounds, unlike the others, and not used as fuel in metabolic reactions. Humans need: calcium, chloride, magnesium, phosphorous, potassium, sodium and sulfur. Foods such as milk, some meats, legumes and vegetables are the best sources of minerals.

anabolism - ✔set of reactions that make larger molecules by combining smaller molecules.

How is the energy released from the breakdown of glucose used by the body? - ✔The energy is released during the breakdown of glucose is used by the body to add a phosphate to an ADP molecule and make ATP. Describe cellular respiration - ✔During cellular respiration, glucose combines with oxygen to form carbon dioxide, water and ATP. Glycolysis - ✔glucose is broken down into two pyruvic acid molecules and two ATP molecules are formed Citric acid cycle or TCA cycle - ✔the pyruvic acid product of glycolysis is converted to carbon dioxide forming some additional ATP electron transport chain - ✔hydrogen atoms formed during glycolysis and TCA cycle are converted to water releasing energy which is used to add phosphate to ADP to form ATP How is the energy released in the breakdown of glucose converted to a for usable by cells? - ✔allows the body to add a phosphate to ADP molecule and make ATP which is then used by cells as a source of energy to perform cellular activities How does the energy formed in fat catabolism compare to that formed in carbohydrate metabolism? - ✔lipid metabolism yields twice the energy formed during glucose metabolism.

Name, tell the location of and explain in detail the first stage of lipid breakdown. - ✔Lipid metabolism occurs in the liver by a process known as beta-oxidation to form acetic acid which is further catabolized by the TCA cycle to carbon dioxide forming some ATP. Why are proteins not usually used a body energy source and when are they used? ✔proteins are the building blocks for the cells and are therefore preserved by the body only being used to make ATP when carbohydrates and fats are unavailable.

What is the first step in the oxidation of an amino acid formed from a protein? - ✔An amino group is removed from the protein to form ammonia.

Explain in detail how ammonia is removed from the body - ✔ammonia is combined with carbon dioxide to make urea which is excreted in the urine.