Humans are the only species that have, "this urge", to inhale harmful smoke into their body. There are all types of smokers. Some smokers are casual smokers, who only smoke in a social scene, other types of smoker are depressed/stressed smokes, who smoke, because they feel that it relieves something in them, and finally there are addictive smoker, who don't know why they even started, but they can't stop. What these people don't realize is that the harm they are putting their bodies through. There are many risks of smoking, like lung disease, heart disease, and risks in pregnancy to the unborn child.
Today it is known that cigarette smoking is the leading cause of lung cancer and death in the United States. One researcher has described cigarette smoking as causing "a chronic inflammatory disorder of the lower airways."(Doll 901-911) When we breathe, air enters the upper airway through the nose and mouth, where the air is filtered, warmed and humidified. The inhaled air travels though the trachea to the lungs. Inside the lung there is a main stem called the bronchus and little air sacs called bronchioles. (Together it looks like a main stem with a bunch of grapes.) Oxygen is exchanged for carbon dioxide in the blood; the blood then carries oxygen to all the body tissues. (Sherman 355) The respiratory system has several built in safeguards to protect it against disease. The filtering that takes place in the upper airway helps prevent infectious and irritating substances from entering the lung. The trachea and the lung produce mucus, which helps trap and carry away contaminants. These contaminants are moved through the lungs by cilia, which are tiny hairs that beat rapidly back and fourth. When smoke is inhaled through the mouth, smokers automatically bypass the first safeguard, the filtering action of the nose. While smokers often produce more mucus in response to smoking, they are less able than nonsmokers to move the mucus out of their respiratory system. This happens because cigarette smoking paralyzes and eventually destroys cilia. It also changes the makeup of the mucus-secreting glands and consequently the mucus itself. In addition, mucus glands sometimes become plugged and less able to produce mucus. The end result is that smokers' mucus, contaminated with potentially harmful substances, is more likely to become trapped in the lung tissue. (Sherman 355) Smoking impairs lung growth and lung tissue in children and adolescents. Another type of lung-growth impairment occurs in smokers' aged 20 to 40. During this stage of life, the lungs undergo a type of growth called the plateau phase. This phase is shortened in smokers, which shortens the time with which tobacco- induced diseases develop. Smokers who take up smoking at younger ages are more apt to suffer smoking-related disease after shorter periods of time than are smokers who begin smoking later in life. (Peterson 215-218)
Twenty percent of people who smoke get...