MUSCLE PHYSIOLOGY

Detailed explanation-1: -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-2: -Neurons in the nervous system can be divided into white matter and grey matter. The white matter of the nervous system is named for its white appearance due to the coating of myelin around its axons. Grey matter on the other hand does not have myelin and thus appears grey instead of white.

Detailed explanation-3: -Nodes of Ranvier are found in myelinated nerve fibres. These are the gaps between two adjacent myelin sheaths. Q. Assertion :Non-myelinated nerve fibres do not possess nodes of Ranvier.

Detailed explanation-4: -Node of Ranvier are the periodic gaps present in the form of narrow areas in the insulating myelin sheath on the axon of a neuron. At the nodes of Ranvier the cell membrane is exposed i.e is non-myelinated.