 |
|
Long(er) term
The human brain is the primary organ responsible for our thoughts, feelings, behaviors and decisions—including the decision to smoke or not! In order to coordinate its many functions the brain has an elaborate system of chemical messengers to communicate between nerve cells. On the surface of each nerve cell are receptors. These receptors are like keyholes into which specific chemicals fit. When the correct chemical finds its receptor, the cell responds by transmitting a message on to other cells. Nicotine, the primary addictive agent in tobacco smoke, mimics the effects of the brain chemical acetylcholine.
Within ten seconds from the first puff of a cigarette the brain is bathed in nicotine. Drugs like injected heroin actually take much longer to have an effect on the brain than does the nicotine from an inhaled cigarette. Specific neurons in the brain that normally respond to acetylcholine now respond to the rush of nicotine, causing both a relaxation of the body's muscles and a mental alertness. The flood of nicotine also signals the brain to release other chemical stimulants that tell the brain to continue doing whatever just happened. It is the release of these stimulants that appear to be key to some of nicotine's addictive properties. Because the levels of nicotine in the brain following a cigarette are so high the brain soon gets used to having extra chemical signals floating around and it begins to stop responding to the normal acetylcholine signal. Now in order to function normally the brain requires the additional nicotine. When the nicotine is not present the smoker experiences withdrawal, increased nervousness, lack of concentration, and a craving for more cigarettes.
Over time with each pack smoked smokers increase the risk that the arteries supplying the brain with blood will break or become clogged causing a stroke. The strokes that befall smokers are more likely to be fatal and occur earlier in life than strokes that nonsmokers have. Stopping smoking could prevent one quarter of all strokes, over 61,500 each year in the US. Smoking also decreases the amount and oxygen content of the blood that supplies the brain; this effect is reversed once smoking stops.
National Institute on Drug Abuse
Napier, K. (1996). Cigarettes: What the warning label doesn't tell you. New York: American Council on Science and Health