You've Got Some Nerve! (The body).(Brief Article)

The nervous system is made up of the brain, spinal cord, and nerves. Nerves carry messages from the brain and spinal cord to all parts of the body and back again. The nervous system controls your breathing, heartbeat, digestion, and senses.

Hold your breath for five seconds. Now you are controlling your breathing. But most of the time you don't even think about breathing. So why doesn't your breathing stop? Because your autonomic (aw-to-nom"-ik) nervous system is doing the thinking for you. It controls body actions such as breathing, heartbeat, and digestion, known as involuntary actions.

Now make a fist. You are in charge of that action. You think of the action, and your brain sends messages to the muscles needed to make a fist. This is a voluntary action.

Learning About Your World

Your nerves also take messages from your five senses to the brain. The brain then tells you what you are seeing, hearing, tasting, smelling, or touching. If one sense isn't working, the other senses and the brain can often adjust for it. For example, if a person can't see, he or she can often use the other senses quite well to learn about the world.

When you touch something hot, sharp, or rough, your nerves quickly send a message to your spinal cord.

The spinal cord responds by sending a signal to the muscles to move away. The ...