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Multiple Sclerosis and AP Conduction


​Myelin sheaths are important for action potential conduction. They insulate the axons, only leaving the nodes of Ranvier free of myelination. As the nodes of Ranvier have many voltage-gated sodium channels, the action potential can “jump” from one node to the next as the inward current produced at one node depolarizes the membrane to the threshold at the next node. Such jumping of action potentials or action potential conduction is impossible without myelin sheaths. Multiple sclerosis is a disease partially caused by deteriorated myelin sheaths.

Based on this information, which of the following is FALSE about multiple sclerosis (MS)?


MS disrupts signaling within the central nervous system.


MS only affects the brain, leaving the spinal cord untouched.


MS patients have relatively intact neurons.


MS is an autoimmune disease, in which myelin sheaths are hardened and lose their insulation function.