Structure of Nervous System

The nervous system is present throughout the whole body, relaying messages from the brain to body systems. It can be divided into two sections, the central nervous system (CNS) and peripheral nervous system (PNS).

• CNS is comprised of the brain and spinal cord, shown in the adjacted diagram as dark purple

• PNS is made up nerves and ganglion, that is all nervous tissue outside of the CNS - shown in the diagram in dark green

 

Further information on the CNS and PNS can be found on the 

Nerves & Spinal Cord page.

 

Functions of the Nervous System

The nervous system has four basic functions:

1. Maintaining and establishing mental activity: the brain is the centre of all mental activity such as memory and thinking.

2. Maintaining homeostasis: the nervous system responds to sensory input of the internal and external body environment by inhibiting or activating systemic processes. This maintains a constant internal environment, ensuring it stays within appropriate physiological ranges.

3. Controlling muscles and glands: major skeletal muscle movements are controlled by the nervous system. It can also contribute to the contol of glands, smooth muscle and cardiac muscle.

4. Receiving sensory input and integrating information: sensory receptors monitor the internal and external environment. The nervous system then integrates this information and initiates a response.