Question:easy
In multiple sclerosis, the slow conduction of motor and sensory pathways is due to?
In multiple sclerosis, the slow conduction of motor and sensory pathways is due to?
Show Hint
What insulating layer must be intact for fast saltatory conduction?
Updated On: Jun 23, 2026
- Defect in the node of Ranvier
- Loss of myelin sheath
- Leaking of sodium channels
- Leaking of calcium channels
Show Solution
The Correct Option is B
Solution and Explanation
Picture the wiring analogy: myelin is the insulation on a wire that lets the signal leap between nodes (saltatory conduction). Strip the insulation, as multiple sclerosis does to CNS axons, and the leaping fails, so conduction slows or blocks. That makes loss of the myelin sheath, option (b), the answer.
Multiple sclerosis is an autoimmune attack on central myelin, producing demyelinating plaques that scar over time, hence the name sclerosis. The clinical result is slowed and sometimes blocked transmission across both motor and sensory tracts, explaining the variable weakness, numbness, and visual symptoms. The distractors describe finer phenomena: nodal defects and ion-channel leaks can follow demyelination but are not the defining cause that the question asks for. The single best answer is destruction of the myelin sheath.
Ref: CNS demyelination physiology.
Multiple sclerosis is an autoimmune attack on central myelin, producing demyelinating plaques that scar over time, hence the name sclerosis. The clinical result is slowed and sometimes blocked transmission across both motor and sensory tracts, explaining the variable weakness, numbness, and visual symptoms. The distractors describe finer phenomena: nodal defects and ion-channel leaks can follow demyelination but are not the defining cause that the question asks for. The single best answer is destruction of the myelin sheath.
Ref: CNS demyelination physiology.
Was this answer helpful?
0
