he function of nervous system is to coordinate the activities of our body. It is the control system for all our actions, thinking and behaviour. The nervous system helps all other systems of our body to work together.The nervous system is like a manager inside our body. Its job is to control and coordinate the parts of our body so that they work together, doing their job at the right time.

Our nervous system coordinates muscles so that we can do things which need thinking like reading, writing, cycling or dancing. The nervous system also coordinates things which we don't have to think about, like heart beat and breathing.

The human nervous system receives information from the surroundings, processes it, interprets it and then responds accordingly. The nervous system also passes information from one internal system to another. For example, as soon as we put food in our mouth, it immediately causes the release of saliva from the salivary glands.

The Unit of Nervous System: Neuron :

The units which make up the nervous system are called nerve cells or neurons. So, neuron is the structural and functional unit of the nervous system. We can now say that nervous system is made of special cells called neurons. Neuron is the largest cell in the body (which looks like an electric wire). Neurons contain the same basic parts as any other animal cell but their structure is specially adapted to be able to carry messages over large distances in the body quickly. The neurons carry messages in the form of electrical signals called electrical impulses or nerve impulses.

A neuron (or nerve cell) has three components:

(ii) Dendrites, and

(iii) Axon.

The cell body of a neuron is like a typical animal cell which contains cytoplasm and a nucleus. A number of long and thin fibres are stretching out from the cell body of a neuron. They are called nerve fibres.

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