The Nervous System

Lesson Plan - Get It!

Audio:

Just like the electrical lines and cables outside that are responsible for moving information to and from your house, there is an electrical system in your body that moves messages and data.

If you missed or need a refresher on previous The Human Body lessons, find them under Related Lessons in the right-hand sidebar.

Your nervous system uses information collected from your environment to help your body learn. There are two parts of the nervous system: the central nervous system and the peripheral system. These two parts work together to make sure that the body is working properly and responding to changes in the environment, like when it gets really hot or cold outside.

The central nervous system is comprised of the brain and the spine. The brain and spine are cushioned by a special liquid, called cerebrospinal fluid, that protects them from damage and injury. This is kind of like the packing peanuts we use in boxes when we mail important packages. It keeps the brain and spine cushioned and protected.

Your brain is made up of nerve cells that take in information collected by nerves that run throughout your body. Your brain then provides instructions for an appropriate response, like shivering when it is cold.

The brain connects to the spinal cord, that runs from your neck to your pelvis. It is a pathway between the brain and the nerve cells in your arms and legs. If you feel in the middle of your back, you can feel the vertebrae that make up your spine.

Once messages have moved from the brain to the spinal cord, they are then sent to the body by the peripheral nervous system. The peripheral nervous system makes sure the heart is contracting, and that voluntary muscle movements in your fingers and legs are controlled. All of these nerves are made up of neurons, specialized cells designed to allow for movement of electrical impulses from one end to the other.

Notice how the cell has many branches. Each branch allows for faster movement of information through the body. Between two neurons is a special space called a synapse. This is an area with a neurotransmitter, which is kind of like a computer in your body that helps identify the type of information being sent, and where in the body it needs to go. Watch Dr. Rajiv Juneja's explanation of What is a neurotransmitter? to learn more about how these cells communicate:

Nerves also collect information from the outside world and send messages back to the brain along the same pathway. This is how you know to sweat when you become hot, and shiver when you become cold. The central nervous system and the peripheral system work together to ensure that your body is identifying and responding appropriately to changes in your environment. Each part of your nervous system has a specific job that helps with communication of information and response to the environment.

• Without your nervous system, how would your body respond?
• Which part do you think is the most important part of the system?

Discuss your response with a parent or teacher, or reflect in your notebook, before moving to the Get It? section, where you will review the major components of the nervous system.