The basic unit of the nervous system is the neuron, a nerve cell specialized in handling information. Neurons sense the environment, communicate information about the environment to other neurons, and send commands to other parts of the body, such as muscles. They accomplish many of these functions through electrical signals. To learn more about these signals, check the background sections on the Resting Potential and the Action Potential.

A neuron is generally made up of the following parts:

• The cell body is the main body of the neuron and contains its nucleus.
• The dendrite is a branch-like structure on the cell body that receives input from other neurons and the environment.
• The axon is a long, thin tube extending from the cell body that transmits information over long distances.
• The synapse is a specialized region where information is transferred from one neuron to another neuron, or muscle.