Functions of the Spinal Cord
The spinal cord has three major functions: maintaining repetitive, coordinated skeletal muscle contractions; serving as a center for spinal reflexes; and conducting information to and from the brain. The nerve tracts of the spinal cord provide a two-way communication system between the brain and body parts outside the nervous system. The tracts that carry sensory information to the brain are called ascending tracts, and those that conduct motor impulses from the brain to the muscles and glands are called descending tracts.
All nerve fibers in a given tract have a similar origin, destination, and function.
Many of the fibers exhibit decussation - they cross from one side of the body to the other within the spinal cord or the medulla oblongata. Not all spinal nerve fibers decussate. Those that do not cross remain on the ipsilateral side of the body.