A neuron is the basic structural and functional unit of the nervous system. A neuron consists of Cyton, Dendrites and Axon.
Cyton : It has a central nucleus with abundant cytoplasm called neuroplasm. The cytoplasm has large granular body called Nissl’s granules and the other cell organelles like mitochondria, ribosomes, lysosomes, and endoplasmic recticulum.
Dendrites : These are the numerous branched cytoplasmic processes that project from the surface of the cell body. They conduct nerve impulses towards the cyton.
Axon : The axon is a single, elongated, slender projection. The end of axon terminates as fine branches which terminate into knob like swellings called synaptic knob. The plasma membrane of axon is called axolemma, while the cytoplasm is called axoplasm. It carries impulses away from the cyton. The axons may be covered by a protective sheath called myelin sheath which is further covered by a layer of Schwann ceils called neurilemma. Myelin sheath breaks at intervals by depressions called Nodes of Ranvier. The region between the nodes is called as internode. Myelin sheath acts as insulator and ensures rapid transmission of nerve impulses.
