PATHOLOGY

Detailed explanation-1: -In this region, the axon is not covered by myelin.

Detailed explanation-2: -Peripheral nerves This composite structure of the axon and a sheath of Schwann cells is the nerve fibre. The axons range in diameter from <1 to 20m. The smallest axons, surrounded by columns of Schwann cell processes, are the non-myelinated nerve fibres and are the most common.

Detailed explanation-3: -The myelin sheath itself is made up of spirally arranged lamellae in which the intraperiod and dense lines alternate. Inside the myelin sheath an inner cytoplasmic process surrounds the axon and where the external surfaces of its bounding membrane come together an internal mesaxon is formed.