Myelin is an insulator sheath for nerve axons. It is composed of phospholipid lamellae, and offers isolation to the axons, ensuring rapid conduction of nerve impulses.

Figure 1. The structure of a myelinated axon

Axons can be either covered by myelin (myelinated) or bare (unmyelinated). Myelin is found in both the CNS and PNS; however, its composition and means of production are different.

Myelin sheaths are not continuous. They contain gaps which are called nodes of Ranvier (seen above)

Myelin in the PNS and CNS

Both in

Subscribe now to continue reading

Join hundreds of successful students who use Meddists to ace their exams.

Gain access to all of the material and topics, custom-made just for you.

Continue