A neuron is the structural and functional unit of the nervous system involved in conduction of nerve impulses. It is divided into cell body, dendrites and axon. Cell body or the soma has the cell organelles and the nucleus and the two processes called the axon and dendrites emerge from the cell.
If a neuron is compared to an electric cord, the myelin sheath can be compared to the insulator of the electric cord. Myelin is a lipid rich substance that insulates the nerve axons. The myelin sheath insulates the nerve axons to increase the speed of transmission of nerve impulse. It is formed by the concentric wrapping of Schwann cell around the axon.