Main->Readings->5th Grade Readings->Control Systems ->Part 4
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Nerves are sending messages all over your body. Your brain is constantly working, thinking, and sending out and receiving signals. Your endocrine system is making and releasing hormones, so that your blood stream is full of chemicals. Yet your body balances all of these things very carefully, noticing changes and sending out signals to keep the body steady. You can help it stay healthy by eating properly, getting regular exercise, and getting enough sleep.
Sometimes, however, even when they do everything right, people can become ill. Then people often take medicines to cure the illness or make themselves feel better while they are ill.
Medicines are part of the group of things we call drugs. A drug is a chemical taken into the body which causes changes in the body. Because the body's nervous system and endocrine system are so complicated, drugs can be helpful, but they can also cause many problems.
When properly used, medicines can be helpful. Some medicines are available over-the-counter, which means they can be bought without a doctor's order. Examples of these are aspirin, antacids, and antihistamines.
Other medicines are only available by prescription, which means a doctor's order is required to buy them. Examples of these are medicines like codeine and some antibiotics.
Many times, things are sold which are not medicines, yet people use them as if they were medicines. These are sometimes called "herbal" medicines or "nutritional supplements." Examples of these are herbal teas and vitamins. These drugs are not controlled by the government because they are not supposed to be drugs at all. Many of them do contain drugs or substances which act like drugs, however.
Just because something is available over-the-counter or is "herbal," that does not mean it is safe to take. No medicine is completely safe. In order to take medicines safely, people must read the directions on the container very carefully. If the medicines are prescription, they must follow the doctor's orders.
Even when drugs are taken properly, they have side effects. A side effect is a drug result that is not intentional. You might not want to irritate your stomach when you take aspirin, but you do; you might not want to get sleepy when you take an antihistamine, but you do. These are examples of side effects.
Sometimes people use drugs improperly. Sometimes they do it by mistake, because they do not read the directions or because they do not believe the directions. Other times, people deliberately misuse drugs. Whether it is on purpose or by mistake, this can cause problems. As you probably realize by now, some of the problems are caused because drugs can change the way the nervous system and endocrine system work.
The deliberate misuse of drugs is called drug abuse. Some drugs cause addiction. Addiction happens when the drug changes the way the brain acts, and causes the drug-taker to feel the need to take more. Frequently, people who abuse drugs become addicted.
There are a number of drugs which are commonly abused. Many of these drugs act like neurotransmitters. Neurotransmitters are the chemicals in the brain which carry messages between neurons.
Stimulants, for instance, are drugs which speed up the action of the nervous system. They make the heart beat faster, and make a person feel more alert. This group includes cocaine, but it also includes caffeine and nicotine.
The depressants are another type of drug which is frequently abused. Depressants slow down the nervous system, making the heart beat more slowly, and sometimes making a person feel confused and sleepy. A common depressant is alcohol.
Another group is the hallucinogens (Huh-LOO-sih-nuh-jenz). These drugs can make a person see, hear, or feel things differently. A mild hallucinogen is marijuana (mar-ih-WAH-nuh), and a stronger one is LSD.
The opiates (OH-pee-ates) are another commonly misused drug. Opiates, like depresssants, also slow down the nervous system. In addition, they often take away pain. Examples of opiates are heroin, morphine, and codeine. They are often abused because they are very addictive. People who inject opiates into their bloodstream run a very high risk of getting diseases of the blood, such as AIDS and hepatitis.
All of the drugs discussed so far affect the nervous system, but there are also drugs which affect the endocrine system. The most well-known type is the anabolic steroids (ANN-uh-bol-ick STEE-royds). These drugs are artificial imitations of testosterone. They cause the body to build muscle. However, anabolic steroids can also cause heart attacks, liver damage, acne, hair loss, and some other peculiar effects you might not expect. There are other types of steroid, such as cortisone, which are used as medicines and can be very helpful. However, cortisone can also have side effects.
You can see that the question of drug use and abuse is a very complicated one. Many of the most dangerous drugs are illegal. Does this mean that if a drug is legal, it is good for you? No, it does not. Many legal drugs also have serious side effects and can be dangerous for you.
In the long run, the most sensible thing to do is to be careful about what you take into your body. When you use a medicine, read the instructions. If it is a prescription, follow the doctor's orders. Keep yourself well informed, and do not depend on "word-of-mouth" for your information. Many people, even otherwise very smart people, can be very silly when it comes to drugs.
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This page last updated August 15, 2002