The brain and spinal cord make up what is called the central nervous system. The two main kinds of nerves are sensory nerves and motor nerves. Sensory nerves carry signals from the sense organs to the brain or spinal cord. The spinal cord runs from the brain to the pelvic area. The eyes, ears, nose, mouth and skin are sense organs.
Motor nerves carry messages from the brain and spinal cord to various parts of the body.
Every movement we make and every thought we have involves the nervous system in some way.