How smoking can cause lung cancer?

How smoking can cause lung cancer?

Tobacco is primarily smoked for inhaling nicotine which is supposed to be a stimulatory compound. Researchers have shown that in small quantities nicotine can activate the nervous system and also have a soothing effect for the strained nerves. But pure nicotine is a highly poisonous substance. For instance, pure nicotine present in one cigar can prove fatal if it is directly injected into the blood stream.

Lung cancer-This is a most serious effect found in people who are long time smokers.

Even passive smokers(persons who are closely associated with smokers ie., who inhale the smoke released by the smokers) are prone to this dis­ease. Polycyclic hydrocarbons are harmful to lungs. Chewing tobacco leaves or gutkas or pan masalas mixed with tobacco is known to cause cancer of the mouth.