As far back as 1988, the surgeon general identified nicotine as a highly addictive substance that closely resembles the addictive qualities of cocaine and heroine. Whether nicotine is ingested by smoking, chewing or sniffing, its effects remain the same. When smoked, nicotine is quickly absorbed into the bloodstream through the lungs. When sniffed or chewed, the mucous membranes in the nose and mouth serve as the point of entry into the bloodstream. Because this substance is contained in smoke, nicotine can also be absorbed through the skin and enter the bloodstream from there.
Once in the bloodstream, nicotine attaches itself to certain cell receptors throughout the body, called cholinergic receptors. These receptors normally respond to acetylcholine, which is a neurotransmitter produced by the brain. Nicotine's ability to mimic this neurotransmitter is the source of many adverse effects on the body.
Function
Once nicotine enters the body and moves through the bloodstream, its effects on so many cholinergic receptors mean the entire body's central and peripheral nervous system is thrown off-balance. These receptors reside in the brain, in the muscles, in the adrenal glands, in the heart and other organs. As a result, bodily functions such as respiration, heart rate, muscle movements, alertness and memory are all affected.
Nicotine's addictive properties result from the influence this substance has on dopamine secretions in the brain. Dopamine is another neurotransmitter that is directly connected to the pleasure centers in the brain. When nicotine enters the system, dopamine secretions increase in much the same way as when cocaine or heroine is present.
Effects
Nicotine remains in the bloodstream anywhere from two to fours hours after ingestion. Because most people continue to ingest it throughout the day, the cumulative effects of continued use increase its time spent in the bloodstream to six to eight hours. Effects had on the body during this time are increased heart rate, increased blood pressure and increased alertness. After many years of use, any attempt to reduce the amount of nicotine ingested will be met with symptoms of withdrawal.
In addition to the effects caused by nicotine, the presence of carbon monoxide--another substance contained in most tobacco products--plays a significant role. Carbon monoxide reduces the amount of oxygen contained in the bloodstream when nicotine is present. As the cells in the body rely on the bloodstream to deliver needed oxygen supplies, the lack of oxygen results in impaired cell and tissue function that gets worse over time.
Once nicotine enters the body and moves through the bloodstream, its effects on so many cholinergic receptors mean the entire body's central and peripheral nervous system is thrown off-balance. These receptors reside in the brain, in the muscles, in the adrenal glands, in the heart and other organs. As a result, bodily functions such as respiration, heart rate, muscle movements, alertness and memory are all affected.
