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 Nissles granules which contain a group of ribosomes for protein synthesis.
Dendrites: Dendrites are short fibres which branch repeatedly and protrude out of the cell body. They transmit electrical impulse towards the cyton.
Axon: They are long fibres 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.