The Nervous System

The nervous system is a very complex system in the body. It has many, many parts. The nervous system is divided into two main systems, the central nervous system (CNS) and the peripheral nervous system. The spinal cord and the brain make up the CNS. Its main job is to get the information from the body and send out instructions. The peripheral nervous system is made up of all of the nerves and the wiring. This system sends the messages from the brain to the rest of the body.

1.

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.

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.

2.

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.

3.

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.

Neurons have a limited ability to repair themselves. Unlike other body tissues, nerve cells cannot also be repaired if damaged due to injury or disease.

4.

There is another system that works with the brain and nerves to keep the body in order. This is the endocrine or hormone system. It controls the rate we grow, our feelings of hunger, our body temperature, and more. Glands are organs that run the endocrine system. The pituitary gland, the pancreas, ovaries (only in females) or testes (only in males), the thyroid gland, the parathyroid gland, and the adrenal glands are organs that run the endocrine system.