Question

5.

Briefly discuss the structure of myelin and its role in the nervous system (biochemistry

connection to the lecture content)

Answer 1

Myelin is the outer covering of axon in a neuron. Myelin sheath act as electrical insulator. The myelin is composed of mainly cholesterol with 40 % of water and 60 % of lipids. Myelin sheath also contain myelin basic protein which constitutes myelin protein, myelin oligodendrocyte glycoprotein, and proteolipid protein. Glycolipid is the primary lipid of mylein sheath called as galactocerebroside.

Mylein sheath prevents the spreading (loss of) electrical current propagating through the axon from one neuron to another. Myelin increases electrical resistance and increases capacitance of cell membrane and thus prevent the electric current from leaving the axon.