Your nerve system is an extensive network that channels nerve impulses from your brain to virtually every cell that makes up your body. This chart shows some of the integral relationships between the spine, nervous system and the body.
If you think of the brain as a central computer that controls all bodily functions, then the nervous system is like a network that relays messages back and forth from the brain to different parts of the body. It does this via the spinal cord, which runs from the brain down through the back and contains threadlike nerves that branch out to every organ and body part. (www.kidshealth.org)