Question

Which of the following statement is correct for node of Ranvier of neuron?

• A. Neurilemma is discontinuous.
• B. Myelin sheath is discontinuous.
• C. Both neurilemma and myelin sheath are discontinuous.
• D. Covered by myelin sheath.

Answer 1

The correct option is B Myelin sheath is discontinuous.

Myelin sheath is discontinuous because of the presence of nodes of Ranvier. Nodes of Ranvier, the periodic gap in the insulating sheath (myelin) on the axon of certain neurons that serves to facilitate the rapid conduction of nerve impulses. However, nodes of Ranvier interrupt the insulation at intervals, and this discontinuity enables impulses to jump from node to node in a process known as saltatory conduction. Whereas neurolemma is the outermost nucleated cytoplasmic layer of Schwann cells (also called neurolemmocytes) that surrounds the axon of the neuron. Thus, the correct answer is option B.