Central nervous system

 The Central nervous system (CNS) is comprised of the Brain and the spinal chord. It is the 'control centre' for the entire nervous system.

The Spinal Chord:

The main role of the spinal chord  is to act as an intermediate between the peripheral nervous system (PNS) and the Brain. This can be in the form of sensory information being passed from PNS to the brain or the vice versa, which is in the form of motor information.

The Brain

As said above, the Brain will recieve information from the PNS as well as from other nerves like the optical nerve. It's function is to then process this information and decide upon an appropriate response.

Kimball J. (2011) The Human Central Nervous System.

Availbale at: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/CNS.html