The... Spinal Cord!

Your spinal cord is connected to the brain and is about as thick as your finger. From the brain, your spinal cord goes down the middle of the back and is covered and protected by the vertebrae. The spinal cord is surrounded by a clear liquid called cerebral spinal fluid that acts as a cushion.

Receptors in the skin send information to the spinal cord through the spinal nerves. The cells for these nerves are located in something called the dorsal root ganglion. The nerve fibers enter the spinal cord through a dorsal root. Many cells in the nerve of the spinal cord send fibers through the nerve to muscles to control movement.

The nerves inside the spinal cord are grouped together in different bundles called ascending and descending tracts. Ascending tracts in the spinal cord carry information from the body, upwards to the brain, like touch and pain. Descending tracts in the spinal cord carry information from the brain down to control body functions.