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 spinal chord itself is a runs the whole length of the spine, is a tubular bundle of nervous tissue and support cells called neuroglia. The spinal chord is segmented and each segment has a specific function.

The Brain

The brain receives information from the PNS as well directly from nerves such as the optical nerve. It then processes this information and decides upon an appropriate response.