By Sharon Fabian

That three-pound pinkish-gray blob in your head may be ugly but it can do a lot of things. Like a computer, it can figure out math problems, and store and organize information. Like a camera, it can turn patterns of light into pictures. It can also regulate body processes, produce emotions, understand and construct language, and order muscles to move.

If your nervous system, which includes your brain, is the control center for your body, then your brain is its commander-in-chief.

Your brain has three main parts: the large part called the cerebrum, the smaller part in the back called the cerebellum, and the brain stem which attaches the brain to the spinal cord. The large part, the cerebrum, is made up of layers of folds and wrinkles called the cerebral cortex. As the surface of your brain grows, it folds and wrinkles more to fit into its space in your skull. Somewhere between 10 billion and 100 billion nerve cells are at work in your brain. They are powered by the food that you eat and the oxygen that you breathe. In case of a fall, or a blow to the head, your brain is protected by your cranium, also called your skull, and by three protective layers called meninges inside your skull.

Your brain has specialized parts for particular jobs, but some jobs involve many different parts of the brain. Reading is a good example. When you read a word, the light that enters your eyes is seen as an image of the word in the vision center of your brain. Another part of your brain transforms that picture into the right sound pattern for the word. Another part figures out the meaning of the word. If you want to say the word aloud, the message is sent to yet another area that instructs the muscles of your throat and mouth to make the right sounds.

Your brain has specialized areas in its cerebral cortex to receive messages from your five senses, too. Different areas handle sights, sounds, tastes, smells, and touch.

The cerebral cortex, along with another part, the cerebellum, controls movements of your muscles. In the area called the motor cortex, a particular section connects to each part of your muscular system. There is a section for your fingers, a section for your wrist, a section for your arm, a section for your toes, and so on. The body parts that do the most complicated movements get the most brain space. That is why the muscles of the mouth and tongue have a big space on the brain, because they have to make many different movements to speak and eat.

Your brain stem has parts that regulate automatic body processes. Your heartbeat and your breathing are regulated by the brain stem.

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摘自edHelper.com