Effects of Smoking

Cigarette smoke contains thousands of chemicals, including nicotine, tar, carbon monoxide, ammonia, sulphur dioxide and even trace amounts of arsenic. Different components act on different systems: nicotine is an addictive stimulant that raises heart rate and narrows blood vessels, contributing to raised blood pressure and coronary heart disease; carbon monoxide reduces the blood's capacity to carry oxygen, further burdening the cardiovascular system; and tar physically damages the gas-exchange surfaces of the lungs. Carbon monoxide and nicotine together are the substances chiefly responsible for damage to the cardiovascular system, while tar is chiefly responsible for damaging the gas-exchange system. …