Nicotine - Effects on the Body
Effects on the Body
Nicotine is the addictive compound in tobacco. When it enters the bloodstream, either through the lungs, the skin inside the mouth, or the nasal passages, it moves to the brain. There it binds with acetylcholinePronounced uh-settle-KOH-leen; a neurotransmitter that forms from a substance called choline, which is released by the liver. receptors, triggering the release of other neurotransmittersA substance that helps spread nerve impulses from one nerve cell to another. and hormones. Basically, nicotine causes two sensations: stimulation in the thought processes, and general relaxation in the user.
The Need for a Cigarette
The quick-acting nicotine increases the amount of dopaminePronounced DOPE-uh-meen; a combination of carbon, hydrogen, nitrogen, and oxygen that acts as a neurotransmitter in the brain. in the brain. This causes pleasure and relaxation of muscles. At the same time, it enhances norepinephrinePronounced nor-epp-ih-NEFF-run; a natural stimulant produced by the human body. and acetylcholine levels, increasing mental stimulation and suppressing appetite. Nicotine also enhances memory and promotes a feeling of well-being. In other words, the drug stimulates the brain's reward system, making the user "feel good."
When people say that cigarettes help them to concentrate, they are not exaggerating. Nicotine does have that effect. However, the effect wears off quickly unless another dose of nicotine enters the brain. Likewise, nicotine does cause a feeling of relaxation, but this too passes quickly, leading to a craving for more of the drug. Many behaviors are related to the addicting qualities of nicotine. The user, taking a puff on a cigarette, might just feel more relaxed because withdrawal symptoms have been held at bay for another hour.
A Dangerous Habit
Nicotine causes a release of epinephrinePronounced epp-ih-NEFF-run; a hormone that increases heart rate and breathing; also called adrenaline., leading to a faster heartbeat, higher blood pressure, quickened breathing, and higher blood sugar. So while the user may feel relaxed, the body is actually working harder to pump blood and take in oxygen. Over a long period of time, this strain on the heart and elevated blood pressure can lead to heart attack and stroke. The drug also complicates the chemistry of the blood, causing blood vessels to become smaller and blood cells to stick together in clots. This can increase the risk of organ damage and stroke. Over time, nicotine contributes to the build-up of plaque in the arteries, a leading cause of heart disease. The chemicals in cigarette smoke also irritate the throat, interfere with the lung's ability to clear debris and bacteria, and promote nausea and other digestive disturbances.
Most scientists agree that nicotine is the most addictive substance used by humankind—worse than cocaine, although it works in a similar way on the brain's reward centers. (An entry for
cocaine is available in this encyclopedia.) Because nicotine works so quickly and exits the brain just as quickly, it begins to induce cravings in most users within days or weeks of first use. Its effects are particularly strong on those with attention-deficit/hyperactivity disorder (ADHD), for whom it may be calming, and those with depression or a tendency to become depressed. People with those problems have a harder time freeing themselves from a nicotine addiction, so they are advised not to use tobacco at all.
Getting Hooked
Regular tobacco use causes toleranceA condition in which higher and higher doses of a drug are needed to produce the original effect or high experienced., a condition that can lead to heavy smoking or chewing, and to lifestyle changes based on that heavy use. People find themselves spending a great deal of money on tobacco products, using them recklessly (smoking in bed, smoking while driving), and endangering the health of others with secondhand smoke.
At overdose levels, nicotine causes dizziness, vomiting, muscle tremors, convulsions, and paralysis of the lungs leading to an inability to breathe. All of these symptoms can develop within minutes. Tobacco products should be kept out of reach of children and pets. Those using nicotine replacement products should never smoke or chew tobacco at the same time. In addition, great care should be taken with any insecticide or other product containing pure nicotine.
The immediate effects of nicotine are generally mild and pleasurable; the long-term effects of tobacco use are not. Smokers accumulate a huge buildup of tar in the lungs, promoting cancer and clogging the air sacs that transfer oxygen into the bloodstream. The cancer-causing chemicals in tobacco promote growth of tumors in the mouth, on the lips, in the throat, in the lungs, in the esophagus, and elsewhere in the body. Nearly one in five deaths due to heart disease can be blamed on tobacco, and the overall death rate from cancer is twice as high among smokers as among nonsmokers.
More Dangers
People who smoke damage tiny, hair-like structures called cilia that lead to the lungs. Cilia help to remove germs and dirt from the lungs. This leads to an accumulation of mucus in the lungs and bronchial tubes—the famous "smoker's cough." Smokers also suffer more frequent and more serious cases of flu and pneumonia. Heavy tobacco use can cause men to become impotent and their sperm counts to decrease. Tobacco use has also been linked to cancers in the female reproductive organs.
Perhaps the most dangerous aspect of nicotine is the time it takes for the deadly side effects to develop. Most people begin using tobacco as teenagers, a time when they are most vulnerable to peer pressure and subtle advertising techniques. The vast majority of teenagers are enjoying the best health they will ever have in their lives. They cannot imagine growing old, developing health problems, or being at risk for fatal diseases. By the time they begin to understand how fragile the body is, they can already be deeply dependent on nicotine.
Becoming free of nicotine addiction causes immediate and long-term health benefits, including improved breathing, better sensation of taste, healthier teeth and skin, and improved strength. Quitting smoking also lessens the risks of cancer—but not entirely. Sometimes people who have not smoked in years discover that they have lung cancer. The disease is difficult to diagnose in its early stages. The very best way to avoid nicotine-related illnesses is to avoid any use of nicotine at any stage of life. If nicotine use has begun, the sooner it ends, the better the chances of living a long and healthy life.
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