The nervous system is responsible for coordinating the body's actions and regulating its functions. It is made up of the central nervous system, which includes the brain and spinal cord, and the peripheral nervous system, which includes nerves that branch out to the rest of the body. The central nervous system processes sensory information, makes decisions, and sends out instructions to the rest of the body. The peripheral nervous system transmits signals to and from the central nervous system, enabling the body to interact with its environment and respond to changes in conditions.