In multiple sclerosis, loss of myelin impairs electrical signaling along neurons. A drug for the treatment of MS would be most effective if it caused which of the following changes along impaired axons?

Question

In multiple sclerosis, loss of myelin impairs electrical signaling along neurons. A drug for the treatment of MS would be most effective if it caused which of the following changes along impaired axons?
A. An increase in the neuron-firing threshold
B. A decrease in extracellular K⁺ concentration
C. An increase in the density of voltage-gated Na⁺ channels along the axon
D. A decrease in the permeability of the membrane to Na⁺ ions at the node of Ranvier

Accepted Answer

C. An increase in the density of voltage-gated Na⁺ channels along the axon. The correct answer is C. Watch the video for a full explanation from Examkrackers founder Jon Orsay:

Answer

A. An increase in the neuron-firing threshold

Answer

B. A decrease in extracellular K⁺ concentration

Answer

C. An increase in the density of voltage-gated Na⁺ channels along the axon

Answer

D. A decrease in the permeability of the membrane to Na⁺ ions at the node of Ranvier

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