A neurologist observes that a patient's action potential propagation velocity is significantly reduced despite normal ion channel function. Which mechanism explains this phenomenon?

💡 Explanation

Demyelination reduces the insulation around the axon, which impairs saltatory conduction; because action potentials must then propagate continuously rather than jumping between nodes of Ranvier, the propagation velocity decreases. Therefore, demyelination explains the reduced velocity, rather than changes in membrane capacitance, potassium levels, or receptor density.

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