Neurons or nerve cells are the units which make up the nervous system. These are the structural and functional unit of the nervous system. It is the largest cell in the body. It carry messages over large distance in the body quickly. The messages are in the form of electrical signals called electrical impulses or nerve impulses.
A neuron is shown in figure below
A neuron (or nerve cell) has three components
(i) Cell body It contains cytoplasm and a nucleus
(ii) Dendrites These are shorter fibres on the body of a neuron.
(iii) Axon The longest fibre on cell body of a neuron.
The axon has an insulating and protective sheath of myelin around it. A number of long and thin fibres stretch out from the cell body of a neuron called nerve fibres.
