THE CENTRAL NERVOUS SYSTEM

CONTENT

A. Organization of the Nervous System

1. Central Nervous System (CNS)
2. Peripheral Nervous System (PNS)

2. The Brain – Position, Structure and Functions

3. The Spinal Cord – Position, Structure and Functions

Organisation of the Nervous System

In a complex multicellular organism many activities go on almost simultaneously. These activities are coordinated by the endocrine and nervous system. The two systems are linked by the hypothalamus.

The basic structural unit of the nervous system is the nerve cell (neurons). The nervous system is made up of millions of neurons.

The main parts of the nervous system are the central nervous system and the peripheral nervous system.

The Central Nervous System (CNS)

This consists of the brain and the spinal cord. The CNS coordinates the activities of the nervous system. It receives impulses from the organism’s internal and external environment, processes and integrates the information and sends out impulses to appropriate effector organs to take action.

The CNS has millions of interconnected nerves which are of two types;

1. The cranial nerves come out of the brain and enter mainly structures in the head (e.g.