Nicotine (C10H14N2) is a colorless, oily, liquid alkaloid that makes the primary active chemical component of
tobacco. As cigarette smokers take in small amounts of nicotine from inhaled smoke they may undergo some
physiological effects. Nicotine, in small doses, serves as a nerve stimulant aiding the flow of adrenaline. Nicotine,
in larger doses, paralyzes the autonomic nervous system (the part of the nervous system that regulates
involuntary action, as of the intestines, heart, and glands) by stopping the transmission of nerve impulses across
the spaces between adjoining nerve cells. Even larger doses of nicotine can cause death.
On average there is only one milligram of nicotine in each cigarette. This quantity is barely large enough to see,
but it is enough to keep the smoker hooked. Once nicotine reaches the brain it stimulates the release of a
substance called dopamine. Dopamine is a chemical messenger in the brain associated with feelings of pleasure.
This causes the smoker to get high and often leads to addiction.
