Functions of the Nervous System

What are the functions of the nervous system?

The nervous system is our window on the world. The nervous system collects information about the body's internal and external environment, processes that information, and responds to it. These functions are accomplished by the peripheral nervous system and the central nervous system. The peripheral nervous system, which consists of nerves and supporting cells, collects information about the body's external and internal environment. The central nervous system, which consists of the brain and spinal cord, processes that information and creates a response that is delivered to the appropriate part of the body through the peripheral nervous system.

Think about what happens when you search through your backpack for a pencil. Information is sent to your central nervous system about the objects you are touching. Your brain processes the information and determines that the first object you touch is too square to be a pencil. Then your brain sends messages via your peripheral nervous system to the muscles in your hand, commanding them to keep searching.

Imagine the billions of messages that are sent throughout your body at any given moment. The messages may tell you to laugh at a funny joke, or they may tell your brain that it's cold outside. These messages enable the different organs of the body to act together and also to react to conditions in the world around us. How does this communication occur?

FIGURE 31–1 Information Flow in the Nervous System

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