dg-chapter 4 section 1 text

CHAPTER

4 Tobacco

Did You Know That…  More than 50 percent of heavy smokers are under the age of 25 and 41 percent of the heavy smoking males and 39 percent of the females are of high school age.  Even if you smoke a pack of cigarettes a day, your defense mechanisms are so efficient that if you quit today, within six months to a year your lungs would be totally clear of foreign matter.  The number of females between the ages of 14 and 18 who smoke has increased over one thousand percent since 1978.  A pack-a-day cigarette smoker puffs more than 70,000 times a year, repetitively exposing the membranes of the mouth, nose, pharynx and the trachea bronchial tree to over 4000 toxic substances.  It’s been estimated that the number of people who annually die prematurely from smoking is well over 300,000. As a matter of comparison, 55,000 people die each year in automobile accidents, less than 10,300 people die annually from the overdose of all other drugs and less than 3,000 people die of AIDSeach year.  If everyone in America would stop smoking today, there would be 300,000 fewer premature deaths each year in America.  Cigarette manufacturers spend more than 300 million dollars each year in an effort to influence smoking behavior.

Introduction ________________________________________________

Most people start smoking because of social-psychological reasons, but continue to smoke because of physical addiction or habituation and/or mental dependence. You may be surprised to know that most heavy smokers acquired the habit before the age of 20 and relatively few acquired the habit after the age of 30. Another interesting fact is that more than 50 percent of heavy smokers are under the age of 25. Some studies have shown that as much as 41 percent of the heavy smoking males and 39 percent of the females are of high school age. An even more disturbing trend is the fact that the number of women who now smoke is quickly approaching the number of men. According to the latest Surgeon General’s report, the number of females between the ages of 14 and 18 who smoke has increased over one thousand percent since 1978.

CRITICAL POINT: The Office of National Drug Control Policy places the health and social cost of drug use at 67 billion dollars annually.

There is a prolific amount of research that clearly shows that smoking contributes generously to the national morbidity and mortality rates. In simpler terms, smoking can kill you. For instance, if you are a white female, longevity statistics report that you are likely to live to be 76 years of age. However, if you smoke at least 20 cigarettes a day, you can subtract 10 years from this figure. If you smoke and take birth control pills, you can subtract another five years from your life since these two drugs are synergistic to each other. Briefly, if you smoke and take birth control pills, you may only live to the age of 61. Now, if you are a Caucasian male, longevity statistics say you will live to the age of 72. Then again, if you smoke a pack a day, you can decrease your longevity by nine years. And if you use birth control pills...you have more problems than just smoking. If you are a black female, longevity statistics report that you are likely to live to be 70 years of age. Conversely, if you smoke at least 20 cigarettes a day, you can subtract 12 years from this figure. If you smoke and take birth control pills, you can subtract another five years from your life. In other words, if you smoke and take birth control pills, you may only live to the age of 53. Is that scary or what? Well, not as scary as if you were a black male. Longevity statistics indicate that if you are a black male, you will live to be 65 years of age. Smoke a pack a day and you may be dead before you reach 50 years of age. That is too young for anyone to die.

CRITICAL POINT: The link between secondhand smoke (also called environmental tobacco smoke) and disease is well known, and the connection to cardiovascular-related disability and death is also clear. About 22,700 to 69,600 premature deaths from heart and blood vessel disease are caused by other people's smoke each year.

∞ DRUGS in Perspective ∞ ____________________________________________________________

Smoking Advertisements.

Although smoking advertisement has been banned from television, cigarette manufacturers still spend more than 300 million dollars each year in an effort to influence smoking behavior. As you might expect, cigarette advertisements seldom, if ever, deal with the facts about smoking. Rather, they are geared towards presenting people who smoke cigarettes as confident, sexy and successful. Even more ludicrous are the ads that imply an association between smoking and good health…a concept that is in direct contrast to the truth.

How effective are these ads? Very effective! There is a linear relationship between capitol expenditures for advertisement and cigarette consumption, meaning that the more money the tobacco companies dump into advertisement, the more cigarettes they sell.

Interestingly, studies have found that most smokers cannot distinguish one brand from the next. Thus, their choice is not a function of taste, but rather how effectively the brand is marketed.

You might be wondering why there is such a discrepancy between the life expectancy of whites and blacks. That’s easy…white folks don’t do anything. No! I’m just kidding. It is probably because white people get much better medical care during their lives. That is changing though, and the sooner, the better.

If smoking doesn’t kill you, it can sure make you wish you were dead. Smoking clearly posses substantial risks to health. For example, smoking predisposes an individual to such medical disorders such as heart disease, respiratory disease, high blood pressure, peptic ulcers, cancer and blood disorders. That’s just the tip of the iceberg. It has been scientifically estimated that if everyone were to quit smoking, there would be 33 percent fewer cases of coronary heart disease and 70 percent fewer cases of cancer.

On a more encouraging note, more than 55

percent of the smokers older than the age of 50 have kicked the habit. In brief, younger people are taking up the habit at a greater rate while older folks are dropping it at an even greater rate.

CRITICAL POINT: It has been scientifically estimated that if everyone were to quit smoking, there would be 33 percent fewer cases of coronary heart disease and 70 percent fewer cases of cancer.

The obvious question is, “Why is this happening?”

Well, the logical answer is that unlike adults, most young people have not incorporated their vulnerability into their intrinsic value system. When you are young, you think you are indestructible. Let’s be real, kids will do anything…jump off bridges, play with fire, tease bulls… hey can’t help themselves. They are suffering from temporary juvenile behavior insanity. Not surprisingly, as the years wear on, they come to realize that they are not indestructible and that they can be injured…that they indeed have limits. The same thing is true for the cigarette smoker. When a smoker is young, it is hard for him to envision that he can be hurt or die. The young person feels healthy and possesses an abundance of strength and energy.

Yet, as the years pass, the smoker starts to experience the symptoms associated with smoking. Eventually, the person realizes that smoking can be hazardous to one’s health and that smoking can contribute to an early checkout time.

CRITICAL POINT: Mainstream smoke is smoke that is inhaled from a cigarette and exhaled by the smoker.

Another point is that their peer groups and social settings more easily influence younger people than older people…again, temporary juvenile behavior insanity. This is an important point because as I previously mentioned, most people begin smoking because of social-psychological factors. Also, there is considerable research which indicates that role models influence children more than they do adults. For instance, numerous experimental studies have revealed that there is a greater than 50 percent chance of smoking if your parents smoke. There is also substantial evidence to show that children are influenced by people they hold in high esteem. If a child observes a professional athlete or movie star smoking, there is a good chance that this person’s behavior could influence the child’s. As a person grows older, he becomes more autonomous and is influenced less by role models. Accordingly, it is easier for older individuals to quit smoking.

This is not to suggest that it is an easy habit for an older person to break. Kicking the smoking habit is difficult for anyone. It’s just that from a social-psychological stand point, it may be easier for an older person to quit. Well, it doesn’t matter if you are old and feeble or young and foolish. We are going to help you out here. Once you read this chapter, if you smoke, you will definitely want to quit. If you don’t smoke, you will never want to start. That is a promise. So let’s get going.

A Fantastic Voyage through Your Lungs and Heart Before you can fully understand the deleterious effects that smoking can have on your body, it is imperative that you have a working knowledge of how your body functions. Once you acquire an understanding of your cardiorespiratory functions, you will develop greater appreciation of the harmful effects that can develop from smoking. With that in mind, let’s take a look at your cardiorespiratory system and how it functions.

CRITICAL POINT: The Cardiovascular system is an intregal part of almost every part of the body. Therefore, the benefits of cardiovascular fitness go beyond simply strengthening the heart. There is a direct effect that this type of exercise has on the mental processes because of the increased blood flow to the brain.

It always amazes me how many people don’t have the slightest idea as to how they breathe or worse yet, why they breathe. Incredibly, some students believe that oxygen goes in your mouth and then just sort of diffuses through the body…like osmosis or something. With all the misinterpretation and incomprehension concerning the cardiorespiratory system, I thought it would be a good idea to give you a cursory explanation as to how it really functions.

The basic organs concerned with respiration are the nose, trachea, bronchi, and the lungs. Air coming in through the nose and mouth leads through a pathway into the bronchial tube, then to the two bronchi (major pathways leading to the lungs), then to the bronchioles (smaller tubes branching from the bronchi), and finally to the tiny air sacs called alveoli. Check out the diagram I made for you in above.

Just don’t glance at it…really check it out. If you understand the parts and how they work, this is simple stuff. So look at it closely and understand it before going on. Now, the question arises, “How does air get

from the nose all the way to the alveoli?” It doesn’t suck in the same way you suck soda through a straw and it doesn’t get there by magic.

Actually, air is exchanged by creating a pressure differential. The basic principle underlying the movement of air or gas is that it will travel from a high-pressure area to an area of lower pressure. It will also travel from an area of greater concentration to an area of lower concentration. The process is called diffusion and takes place as a result of the pressure gradient or difference. The respiratory muscles and the elasticity of the lungs create the pressure differential that first allows air to flow into the lungs and then allows air to be expelled from the air passages.

CRITICAL POINT: The basic principle underlying the movement of air or gas is that it will travel from a high-pressure area to an area of lower pressure.

Let’s begin with inspiration or the act of taking air into the lungs. First, the diaphragm (that big muscle in the lower portion of your stomach) and the external intercostal muscles (those little muscles that are connected to your rib cage) contract expanding your thoracic (chest) cavity.

Allow me to explain further. It’s not all that hard to understand. When the diaphragm contracts, its dome moves downward, expanding the thoracic cavity from top to bottom. When the intercostal muscles contract, they pull the ribs outward and slightly upward. This movement also enlarges the thoracic cavity from side to side and from front to back. The enlargement of the thoracic cavity causes a decrease in pressure. Air pressure outside the body is then greater than the air pressure inside the body, causing air to flow into the lungs and alveoli until thoracic pressure is equal to the atmospheric pressure.

Now, if you understand all of that, raise your hand. If you don’t, the easiest way to understand this is to think about a balloon under water. What happens to a balloon when you put it under water? It shrinks because of the pressure that the water exerts on the balloon. Does the amount of air in the balloon change? No. It’s still the same. We have the same amount of air in a smaller space. As a result, the pressure in the balloon goes up. Therefore, when you take the balloon out of the water, the size of the balloon expands and the pressure decreases according to the change in the size of the balloon.

The lungs are like balloons such that as the space that holds the air expands, the pressure in them goes down. So, after your diaphragm drops and the intercostals lift the ribs increasing the space in the

lungs, you will have air in your lungs…right? Right! Now, listen closely here. We want you to do well on your test.

Critical Point: The cardiovascular system functions can be categorized into three main functions: transport, regulation and protection. The organs of the system carry out these functions in coordination with the functions of the other systems for the proper functioning of the body.

Now, let’s see how it gets back out. Let’s look at expiration or the expelling of air from the lungs.

Expiration is nearly the opposite of inspiration. In this case, the diaphragm and the external intercostal muscles relax, thereby returning to their original position.

When this occurs, the volume of the thoracic cavity decreases by all parameters, causing the pressure inside the lungs to increase. The pressure in the cavity and lungs now is greater than the atmospheric pressure, which causes air to flow out of the cavity and lungs until the external (atmospheric) and internal (thoracic) pressures are once again the same. If you don’t understand what we are talking about, Simon says, “Read it again.”

Okay, now that you understand how air enters a nd exits the body, the next step is to understand how oxygen is delivered to the tissues of the body. In order to know how that works, you will first have to understand how the cardiovascular system functions. See, you’re getting a real education here.

CRITICAL POINT: There are three different types of blood vessels in the human body, the arteries, the capillaries and the veins. The arteries are of three types, the pulmonary artery, the aorta and the coronary arteries. They perform the function of carrying oxygenated blood from the heart to the other parts of the body, but the pulmonary artery carried deoxygenated blood from the heart to the lungs. The capillaries carry oxygen and nutrients to the tissues and cells of the body and the veins carry deoxygenated blood from the various organs of the body to the ∞ DRUGS in Perspective ∞ __________________________________________________________________ heart.

This system consists of the heart and blood vessels (let’s not forget arteries, capillaries and veins). Check out the picture we have for you on the heart. Look at it closely before you go on. The heart is a fourchambered muscular organ that is roughly the size of your fist. The upper cavities are called atria, while the lower cavities are known as ventricles. Blood comes in from

What is Coronary Circulation?

There is a subdivision of the circulatory system that supplies the heart itself with blood… thereby providing oxygen and nutrients while returning waste products. The coronary arteries leave the aorta and return to the outside of the heart.

Approximately 10% of the blood leaving the left ventricle of the heart flows through the coronary system (roughly 300-400 ml per min.). Incidentally, the blood within the cavities of the heart nourishes only the lining of the heart.

the lower extremities (legs, groin and abdomen) into the right atrium through the inferior vena cava. Blood from the upper extremities (head, shoulders and chest) also empties into the right atrium, but this time through the superior vena cava. The blood at this time has a high concentration of waste products such as carbon dioxide and carbon monoxide and a low concentration of oxygen.

From the right atrium, blood goes to the right ventricle. When the right ventricle contracts, blood is forced through the pulmonary artery, which leads into the lungs. From there, the connection goes off the pulmonary artery branch to smaller vessels called arterioles and off the arterioles branch even smaller vessels called capillaries. These capillaries intermingle with the millions of tiny air sacs throughout the lungs. It is there in the tiny air sacs that the real work of the vascular system takes place. The carbon dioxide in the capillaries is exchanged for the oxygen in the alveoli. Remember, high concentrations always diffuse to low concentrations. The carbon dioxide in the alveoli is then exhaled.

CRITICAL POINT: The cardiovascular system transports oxygen from the lungs to the various cells of the body. The primary function of the cardiovascular system is to transport nutrients from the intestines to the lungs and other parts of the body, and carbon dioxide from the cells to the lungs. Hormones from the various endocrine glands and heat from the cells are also transported by this system. Removal of waste products like carbon dioxide and nitrogen from the body is also performed by this system. This function of transport is mainly carried out by the blood and the network of blood vessels present in the cardiovascular system.

Now, here’s something interesting. Did you ever notice that when you walk around campus all of those little green trees and shrubs follow after you? What do you think they want…your bootie? No! What they want is your carbon dioxide…not your phone number. You see, we have this ∞ DRUGS in Perspective ∞ little arrangement with them. We give them __________________________________________________________________ carbon dioxide and in turn they give us oxygen. If they don’t get carbon dioxide they What is Systolic and Diastolic Pressure? will die and if we don’t get oxygen we will Systole corresponds to the contraction of the die. If you take all the greenery off the face of ventricles.

Ventricular systole causes blood to enter the arteries the earth, we would all die. If you take all the and blood pressure is at its highest during this period (it averages animals and humans off the earth, all the between 110-120 mm of mercury at the brachial artery in a greenery would die. We keep the trees alive healthy adult). by supplying them with carbon dioxide and During ventricular diastole (when the heart momentarily relaxes) blood pressure in the heart decreases and they keep us alive by supplying us with reaches a minimum just before the start of the next systole. This oxygen. They take our carbon dioxide and minimum is called diastolic pressure (it averages between 65-80 through a process called photosynthesis mm of mercury at the brachial artery in a healthy adult). convert it to the oxygen that we breathe. In Blood pressure will be affected by the position of the body. It is standard practice to measure blood pressure while the brief, we need each other to coexist. individual is seated and the arm is about level with the heart.

The oxygen that the blood and the capillaries pick up is then taken back to the

heart through three pulmonary veins and emptied into the left atrium. From the left atrium, the blood then goes to the left ventricle. When the heart contracts, the oxygenated blood in the left ventricle is forced into the aorta, which in turn leads into systemic circulation. As the blood moves through the body, the tissues of the body absorb the oxygen and use it in the metabolic process.

It is good to remember that normally arteries in the body carry oxygenated blood while veins carry deoxygenated blood. The only exceptions are the pulmonary artery that carries deoxygenated blood from the heart to the lungs and the pulmonary veins that carry oxygenated blood from the lungs back to the heart.

CRITICAL POINT: The cardiovascular system performs the function of protecting the body and its organs from infection and diseases by providing white blood cells that have the ability to fight against them. Proteins and antibodies required for destroying viruses, bacteria and disease causing germs are also provided by this system to the various parts of the body. Another important function of this system is to protect the body from excessive blood loss through the process of blood clotting during an injury.

Now, here is something else you may not know. The heart does not get its oxygen from inside its chambers. The blood actually leaves the heart and then returns to “feed� itself through coronary vessels.

There is a subdivision of the circulatory system that supplies the heart with blood, providing oxygen and nutrients while returning waste products. When the blood leaves the heart, coronary arteries branch off from the aorta and return to the outside of the heart. This is called coronary circulation. Approximately 10% of the blood leaving the left ventricle of the heart flows through the coronary system (roughly 300400 ml per minute). By the way, the blood within the cavities of the heart nourishes only the lining of the heart.