Nicotine is the chemical substance contained in tobacco and is a strong poison, which acts on the nervous system. Smoking tobacco is habit which associated with the inhalation of tobacco smoke, and promotes the development of heart disease, blood vessels, stomach, lung and leads to cancer. By the way nicotine is the second typical false friend. There are cases when smokers die from lung cancer resulting from smoking and knowing about it, begged doctors to allow them to smoke “just one” cigarette.
Nicotine is one of the strongest poisons of plant origin. Rabbit dies from 1 / 4, and the dog dies from 1 / 2 drops of nicotine. For a man a lethal dose is 50-100 mg, or 2-3 drops of nicotine. This dose enters the blood of those who smoked 20-25 cigarettes a day (one cigarette containing 68 mg of nicotine). Smokers do not die because the poison is introduced gradually, and some other venom is neutralized by nicotine tobacco – formaldehyde. The gradual introduction of nicotine into the body is getting used to it. Nicotine is included in the metabolism. Quitting smoking is accompanied by rather strong and unpleasant reactions, similar to some extent with “brittle” in drug addicts. It is called “withdrawal syndrome”.
Nicotine reaches the brain within 7 seconds after the delay. It stimulates all the central system and can cause hand tremors, but with significant dose, and convulsions. At first, nicotine increases cerebral blood vessels. This is accompanied by improvement of its supply, resulting in a feeling of freshness and vigor. But soon vasodilatation follows by constriction. For the brain excitation there follows its inhibition. Man feels the need to reintroduce nicotine. So there is strong nicotine dependence.
Smoking causes quickening of the heart, increase in muscle tone of vascular walls, blood pressure, blood clotting, which promotes the formation of blood clots and lead to the development of atherosclerotic disease, heart attacks and strokes, to circulatory disorders of the brain. Nicotine increases the secretion of adrenalin adrenal cortex, which causes an increased flow of glucose in the blood and inhibits the sensation of hunger. Smoking reduces the content of vitamin B4, B12, C in blood, as a large number of them spent on de- intoxication of chemicals (about 3000) contained in tobacco smoke. Some of these substances can damage living tissue. Statistics show that smokers have 2-5 times more likely to be blinded to age 50 than non-smokers. Smoking teens primarily affects the nervous and cardiovascular systems. 12-15 years of addiction to tobacco has already complained of shortness of breath during physical exertion. People, who started smoking before 15 years, die from cancer five times more than those who started smoking after 25 years. Smoking is particularly harmful to the female body.