We'll now look in detail at the central nervous system which consists of the brain and spinal cord. It is responsible for the integration of all nervous activities in the body.

The brain lies within the cranial cavity (the space inside the cranium, or skull). Its various regions are in communication with each other and may function together. However, it is usual to consider the brain as consisting of three distinct areas:

• the cerebrum,
• the brainstem,
• the cerebellum or hindbrain.

We'll look at each of these in turn.