Central Nervous System

Brain

The brain keeps the body in order. It helps to control all of the body systems and organs, keeping them working like they should. The brain also allows us to think, feel, remember and imagine. In general, the brain is what makes us behave as human beings.

The brain communicates with the rest of the body through the spinal cord and the nerves. They tell the brain what is going on in the body at all times. This system also gives instructions to all parts of the body about what to do and when to do it.

Spinal Cord
Nerves divide many times as they leave the spinal cord so that they may reach all parts of the body. The thickest nerve is 1 inch thick and the thinnest is thinner than a human hair. Each nerve is a bundle of hundreds or thousands of neurons (nerve cells). The spinal cord runs down a tunnel of holes in your backbone or spine. The bones protect it from damage. The cord is a thick bundle of nerves, connecting your brain to the rest of your body.

Central Nervous

"Senses"

Senses

There are five main senses - touch, smell, taste, hearing and sight. These are the external sensory system, because they tell you about the world outside your body. Your senses tell you what is happening in the outside world. Your body's sense organs constantly send signals about what is happening outside and inside it to your control center - the brain.

The cerebrum is part of the forebrain. The cerebral cortex is the outer layer of the cerebrum. Certain areas of the cerebral cortex are involved with certain functions.

Sensory areas such as touch, smell, taste, hearing and sight receive messages from the skin, nose, mouth, ears and eyes. We feel, taste, hear and see when these messages are received by the sensory parts of the brain.

The Peripheral Nervous System

The nervous system is made up of nerve cells or neurons that are "wired" together throughout the body, somewhat like communication system. Neurons carry messages in the form of an electrical impulses. The messages move from one neuron to another to keep the body functioning.