MEDICAL PHYSIOLOGY

Detailed explanation-1: -"Nodes of Ranvier” is the name given to the intermittent unmyelinated gaps along the axon. The nodes of Ranvier exist because of differences in the structure or function of the axon, myelin, and Schwann cells in these “gap” areas.

Detailed explanation-2: -The segment between nodes of Ranvier is termed as the internode, and its outermost part that is in contact with paranodes is referred to as the juxtaparanodal region.

Detailed explanation-3: -The nodes of Ranvier are characterized by short (1um), specialized regions in the axonal membrane that are not insulated by myelin. Although it is bare of myelin at the node, the axon is in direct contact with the microvilli of the Schwann cells in the PNS, or with processes of astrocytes in the CNS (Figure 1).

Detailed explanation-4: -Key Points. The nodes of Ranvier are specialized axonal segments that lack myelin, allowing the saltatory conduction of action potentials.