The main active ingredient in tobacco is nicotine, an alkaloid, which allows plants natural defense against pests and for centuries used as an insecticide. Nicotine can enter the body through inhalation of smoke and chew. Thus quickly it comes to the brain where it acts stimulating, that improves the blood supply to the brain, the current concentration, and memory and reduces anxiety, and at the same time acts mesmerizing.
Nicotine also irritate the lining of the respiratory tract of the stomach, increases blood pressure and causes a decrease in body temperature. As a result of the feeling of pleasure in the brain addictive. Rapidly decomposes and creates a tolerance, so after a few hours the body again demands nicotine, but if during the day enter to a greater extent not brings benefits, but comes to saturation and the occurrence of discomfort and usually severe headache. In the mid-20th century tobacco smoking was extremely popular, and then little by little began too many diseases associated with this habit.
Today the World Health Organization warns of the extreme dangers of smoking for those who smoke as well as those who only inhaled the smoke. Namely, the tobacco causes numerous physiological effects, particularly addictive, and because of the exceptional strength in the manufacture of cigarettes add various additives for odor, taste, stability, speed of burning, etc.
The combination of burning tobacco with all those additives creates smoke that has more than 4,000 different chemical compounds, of which 250 harmful carcinogens 50 and contains tar and carbon monoxide. Today it is proven that smoking causes or accelerates the occurrence of diseases of the mouth, throat, lungs, heart attack or stroke and cancer of the lung, mouth and throat and is believed to be linked to the emergence of other forms of cancer, especially of the pancreas, stomach and bladder. According to reports from the World Health Organization in July 2013, tobacco kills half of its consumers.
As a result of the strong media campaigns against smoking, in developed countries today it is unpopular, but in poor countries continues to grow usage. Smoking is considered a major threat to public health, and some data suggest that every six seconds in the world dies from diseases a person is just for stories by inhalation of tobacco smoke.