The structure of neuron : Nerve cells or neurons are the structural and functional units of the nervous system. It consists of three major parts namely, cell body, dendrites, axon.

Cell Body : It is irregular in shape or polyhedral. It contains cytoplasm and certain granular bodies called Nissl's granules which contain a group of ribosomes for protein synthesis.

Dendrites : Dendrites are short fibers that branch repeatedly and protrude out of the cell body. They transmit electrical impulse towards the cyton.

Axon : They are long fibers arising from the cell body with a branched distal end. It terminates in a synaptic knob. It is filled with neurotransmitters.

Parts of axon : (a) Axoplasm : It is the cytoplasm of an axon.b. Myelin sheath: It is made up of many layers of Schwann cells.
(c) Neurilemma : The outermost layer of Schwann cells.
(d) Nodes of Ranvier : These are gaps left by a myelin sheath.