Question

Which of the following statements is correct for the node of the Ranvier of nerve?
A. Neurilemma is discontinuous
B. Myelin sheath is discontinuous
C. Both neurilemma and myelin sheath are discontinuous
D. Covered by a myelin sheath

Answer 1

Hint: The neurilemma is the outermost layer of nucleated cytoplasm of the schwann cells which surround the axon of neurons. They are the gaps in between the myelin sheath where axons remain uncovered. This is because the myelin sheath is largely made up of fatty substances. The ranvier's nodes permit the fast electrical impulse generation along the axons.

Complete answer:
The presence of nodes of Ranvier in a myelin sheath. It is the periodic gap in insulating myelin on the axon of the specific neurons that work to facilitate the rapid conduction of nerve impulses. Therefore, nodes of Ranvier disturb the insulation at time gaps, and this discontinuity activates impulses to jump from one node to another in a process called saltatory conduction. Whereas, neurolemma is the outer nucleated cytoplasmic layer of the Schwann cells or it is also known as neurolemmocytes, that moves around the neuron. The fibers wrap around the myelin sheath which is a thread-like part of the nerve cells. The sheath, which is protected by the fibers also called axons. Nerve signals are sent and receive quickly when the myelin sheath is healthy.
So, the correct answer is option (B) – Myelin sheath is discontinuous.

Note: Myelin sheath is the part of the fatty molecule which protects your nerve cells. The nerve cells are the sleeves of the CNS, which sends a message back between your brain and the rest of the body. If you are suffering from multiple sclerosis (in which your immune system attacks your central nervous system) can damage your myelin sheath, it can weaken your muscles, and also damage your balance and coordination.