Explain the basic ways that nicotine and carbon monoxide contribute to the development of coronary heart disease (CHD)

Question

What will be an ideal response?

Answer 1

Answer: Cardiovascular Disease Cardiovascular disease includes a number of specific
conditions. Some of these diseases are coronary heart disease (CHD), in which the heart is damaged by the restriction of blood flow through narrowed or blocked coronary arteries; arteriosclerosis, in which the walls of arteries harden and lose their elasticity; atherosclerosis,
in which fatty deposits inside arteries impede blood flow; and ischemic stroke, in which interruption or reduction in blood flow causes damage to the brain.

In all these diseases, cigarette smoking increases the risk dramatically. We know now that smoking is responsible for approximately 30 percent of all CHD deaths. The risk of CHD doubles if you smoke and quadruples if you smoke heavily. On average, smoking also raises the risk of a sudden death (such as from a fatal heart attack) by two to four times, with the degree of risk increasing as a direct function of how many cigarettes are smoked per day. To put it even more bluntly, it has been estimated that unless smoking patterns change dramatically in the
future, about 10 percent of all Americans now alive may die prematurely from some form of heart disease as a result of their smoking behavior. These statistics are strengthened by our understanding of how cigarette smoking actually produces these dangerous cardiovascular conditions. The major villains are nicotine and carbon monoxide. Nicotine, as a stimulant drug, increases the contraction of heart muscle and elevates heart rate.

At the same time, nicotine causes a constriction of blood vessels, leading to a rise in blood pressure, and also increases platelet adhesiveness in the blood. As a result of a greater adhesiveness, platelets clump together and increase the risk of developing a blood clot. When
a clot forms within coronary arteries, a heart attack can occur; a clot traveling into the blood vessels of the brain can produce a stroke. Finally, nicotine increases the body's serum cholesterol and fatty deposits, leading to the development of atherosclerosis. While nicotine is doing its dirty work, carbon monoxide makes matters worse. A lack of oxygen puts further strain on the ability of the heart to function under already trying circumstances.

The general term chronic obstructive pulmonary disease (COPD) refers to several conditions in which breathing is impaired because of some abnormality in the air passages either leading to or within the lungs. Although only 20 percent of smokers in the United States develop COPD, 80 to 90 percent of all COPD cases are the result of smoking. Historically, COPD has
been viewed as "a man's disease," but since 1980 the death rate in women has tripled, and since 2000, more women than men have died or been hospitalized each year as a result of COPD. With the exception of a rare genetic defect, smoking is the only established cause of clinically significant COPD.

Two examples of COPD are chronic bronchitis, in which excess mucus builds up in air passages, leading to an inflammation of bronchial tissue, and emphysema, in which air sacs in the lungs are abnormally enlarged and the air sac walls either become inelastic or rupture, leading to extreme difficulty in inhaling oxygen and exhaling carbon dioxide. In the case of advanced emphysema, more than 80 percent of a patient's energy is required merely to breathe. These two diseases account for more than 100,000 deaths each year, and many additional
thousands are forced to lead increasingly debilitating lives, gasping and struggling each day to breathe. Pulmonary damage, however, is not limited to adults who have been smoking for many years. Cigarette smoking is also associated with airway obstruction and slower growth of lung function in younger populations. Adolescents who smoke five or more cigarettes a day are 40 percent more likely to develop asthma and 30 percent more likely to have symptoms of wheezing but not asthma than those who do not smoke. Among smokers, girls show a greater loss of pulmonary function than boys, even though boys report that they smoke more cigarettes.