Introduction
.Smoking, inhalation and exhalation of the fumes of burning tobacco
Leaves of the tobacco plant are smoked in various ways. After a drying and curing process, they may be rolled into cigars or shredded for insertion into smoking pipes. Cigarettes, the most popular method of smoking, consist of finely shredded tobacco rolled in lightweight paper. About 46 million people in the United States smoke an estimated 420 billion cigarettes each year
Until the 1940s smoking was considered harmless, but laboratory and clinical research has since confirmed that tobacco smoke presents a hazard to health. Smoke from the average cigarette contains around 4,000 chemicals, some of which are highly toxic and at least 43 of which cause cancer. Nicotine, a major constituent of tobacco smoke, is both poisonous and highly addictive. According to the American Cancer Society, smoking is the most preventable cause of death
.in America today
Health Effects of Smoking
About 442,000 people in the United States die each year from illnesses caused by cigarette smoking. Smoking accounts for nearly 90 percent of lung cancer deaths. Additionally, smokers are at increased risk for cancer of the larynx, oral cavity, esophagus, bladder, kidney, and pancreas. While some negative health effects of smoking manifest slowly over time, others can be measured almost immediately. Sticky brown tar leaves yellow stains on fingers and teeth. Some of the inhaled tar is absorbed by lung cells, causing them to die. Tar also damages the cilia in the upper airways that protect against infection. Nicotine causes arteries to constrict, lowering skin temperature and reducing blood flow to the hands and feet. Carbon monoxide deprives the body of oxygen, binding to red blood cells in place of the oxygen molecule and forcing the heart to pump more blood through
.the body
One-third of smoking-related deaths are caused by coronary heart disease or chronic airway obstruction. For example, the nicotine in tobacco combines with carbon monoxide in tobacco smoke to damage the lining of blood vessels and make blood platelets stickier. Platelets form part of the damaging plaque buildup in artery walls. These effects in combination contribute to the development of heart disease. Smoking also increases the risk of stroke by 50 percent—40 percent among men and 60 percent among women. Other research has shown that mothers who smoke give birth more frequently to premature or underweight babies, probably because of a decrease in blood flow to the placenta. Babies born to mothers who smoke during pregnancy are also at increased risk for
.sudden infant death syndrome
Cigar and pipe smoke contains the same toxic and carcinogenic compounds found in cigarette smoke. A report by the National Cancer Institute concluded that the mortality rates from cancer of the mouth, throat, larynx, pharynx, and esophagus are approximately equal in users of cigarettes, cigars, and pipes. Rates of coronary heart disease, lung cancer, emphysema, and chronic bronchitis are elevated for cigar and pipe smokers and are correlated to the amount of
.smoking and the degree of inhalation
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