The brain is a mass of nerve tissue that fills the entire inside of the skull. It is by far the most important organ in the body. Without it, we could not live.
The billions of tiny cells in the brain are remarkable. They remember things for years; they seem to be able to learn endless new things, year in and year out, throughout our lives; they can remember tastes and smells, sights and sounds, and the feel of things for a lifetime without ever forgetting. Once a child becomes familiar with the taste of milk, or the smell of roses, or the sound of a piano, or the sight of the sky, or the feel of an ice cube, he will remember them forever-without even trying.
This is because there is no limit to the ability of our brain cells to understand and to store knowledge.
Just think of some of the brilliant things the human brain has done. For example, it figured out how to send people safely to the moon and back. It invented television, where all we have to do is flick a switch and pictures and voices appear in our own home. And the human brain invented and improved the airplane so that now we can travel safely from place to place in the air rather than on the ground.
All this, and so much more, too, because of the wonderful cells our brains possess. Did you know that we keep the same
brain cells all our lives? We replace our skin cells every few weeks, and our blood cells every few months, but we never replace our brain cells with new ones. When we scratch ourselves or skin a knee, a scab forms, and a couple of weeks later when it falls off, we have brand-new skin underneath. Not so with our brain cells. If anything happens to one of these cells, it is never replaced by a new one.
Nature was clever in having us keep the same brain cells, because it allows us to remember things for always. If we changed our brain cells the way we do our skin cells or blood cells, we would not be able to remember things for very long. New brain cells would have to learn all over again the various senses of taste or smell or sound or sight or touch that the old brain cells had been familiar with since early childhood. Why, we might not even remember our parents from one year to the next.
No one knows for sure how the brain works. For instance, we don’t know exactly where in the brain cell our knowledge is stored. If we were to look at brain cells under a microscope, we could not see anything to show us how they developed the amazing ability to know all the things they know. Some scientists believe that our ability to think and to store knowledge is a chemical reaction, but exactly what that reaction is, we don’t understand. However, doctors do know that the brain won’t work properly unless, at all times, its cells are supplied with a great deal of oxygen and sugar. Brain cells die more quickly than cells of any other organ in the body if they are deprived of oxygen for even a few minutes, and if the brain cells don’t get enough sugar, they can’t function properly.
The four major portions of the brain are the cerebrum, the cerebellum, the pons, and the medulla oblongata. Our thoughts and our movements are controlled by the cerebrum.
The brain is composed of four main parts:
1. The cerebrum controls our thoughts. Even while we are asleep, the cerebrum keeps working, producing thoughts. These thoughts are our dreams. Often they don’t seem to make much sense, because they pay little attention to time, or space, or place. But dreams are created by our brains, so they must have some meaning.
The thoughts we have while we are awake are called conscious thoughts; those we have while we are asleep are unconscious thoughts. The cerebrum also controls our movements and sensations. The motor nerves that move our muscles are in the cerebrum, and the sensory nerves that allow us to feel things are also in the cerebrum.
2. The cerebellum lies beneath the cerebrum in the back of the brain. It controls muscle reflexes and is responsible for our muscles working together so they don’t tug and pull in different directions at the same time. The cerebellum also controls our sense of balance.
3. The pons lies beneath the cerebellum in the base of the skull. It receives and sends out impulses or signals from the cerebrum.
4. The medulla is located under the pons and connects with the spinal cord. It transmits signals received from all the other parts of the nervous system. Doctors learned about the various functions of the different parts of the brain by making experiments. They discovered that brain cells and nerve cells react to electricity. For example, if we supply a small electric current to a nerve, the nerve will send out a signal and the muscle it supplies will contract. In the same way we can stimulate brain cells and, by so doing, obtain information about their function.
Research has revealed the fact that certain areas of the brain are responsible for various specific functions and these areas have been carefully charted. From experiments of this sort, doctors learned that the signals or impulses that travel from one part of the brain to another, or that travel along nerves to and from the brain, work much the same way as electricity traveling along an electric cord.
Of course, we know that the brain and its nerves don’t have to be stimulated by electricity from the outside. We can start our own “current,” without any outside help at all. Here is an experiment that will show you how your brain works:
Place the palm of your hand flat on the table. Now, think about lifting up your hand, but don’t move it. When you see the numbers 1-2-3, lift up your hand.
Now let’s see exactly what happened. First the brain cells in your cerebrum told the nerves going to your hand that you would soon send signals along them. When you lifted your band, your cerebrum started the signal that traveled to the cerebellum, then to the pons, then to the medulla, then to the spinal cord and out to the nerves that control the muscles in your hand and arm. And all this took place in the flash of a second.
Close your eyes and think of a large airplane flying through a cloudy sky. Think hard and imagine you are actu¬ally seeing it. And there it is!
What really happened was that your brain, all by itself, without paper or paint or crayon or pencil, made that picture and you saw it clearly in your own mind.
Teachers and scientists and doctors know that the brain does certain things automatically, but if we want to develop it to its very best, we must train
The cerebrum can do other amazing things, too. For example, it can make imaginary pictures and feel imaginary sensations. Here is another experiment showing how your brain works:
it all the time. If we don’t, it won’t develop nearly as well. Here are some rules to follow to grow up with a fine brain:
1. Always get enough sleep. A tired brain doesn’t work very well.
2. Eat a good, balanced diet. Brain cells need more. nourishment than any other cells in the entire body. A badly nourished body means a badly nourished brain, and a badly nourished brain won’t function well.
3. Control your anger. It has been found that people who lose their temper all the time, or who constantly fight and hate, develop brains that don’t function as well as they might.
4. Follow what your parents and teachers tell you. Listen carefully to what you are told, whether at home or in school. It has been found that children who fail to pay attention don’t learn well, and their brains never develop as well as they could.
5. Read lots of good books.
6. Look at good television shows, and listen to good radio shows, especially those that can tell about new things.
7. Make as many friends as you can. Children with many good friends usually learn much more than those who are lonely or without friends.
8. Try to get along well with your brothers and sisters. For some strange reason, the brain doesn’t develop as well as it should if there is too much quarreling and fighting and arguing in a family.
9. Tell your parents whenever something is bothering you greatly. It is not good for your brain for you to worry too much, or be unhappy for too long a time. In most cases, parents can help you solve your problem without too much trouble. If they can’t, they will take you to a doctor or other counselor who will know how to help you.