PHYSIOLOGY
NEUROTRANSMISSION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Saltatory conduction occurs in myelinated nerve fibers
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During conduction of an action potential, current flows from the active area of the membrane to the adjacent inactive area, thereby decreasing the potential in the inactive area to threshold
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Action potential propagation is faster in myelinated fibers than in unmyelinated ones
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Action potential propagation is faster in large-diameter fibers than in small-diameter ones.
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Action potential propagation is faster for stronger stimuli than weaker stimuli
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Detailed explanation-1: -Answer and Explanation: The correct answer is c. An action potential, once started, cannot be stopped or negated.
Detailed explanation-2: -The only factor that does not affect the speed of propagation of axonal action potentials is a. whether the axon is afferent or efferent (i.e. a sensory vs a motor neuron). The speed of axonal propagation will not be influenced by the type of neuron.
Detailed explanation-3: -Axon diameter, internode distance, and myelin sheath thickness all influence the speed of action potential propagation. Moreover, these factors are to a certain degree correlated with each other.
Detailed explanation-4: -Action potentials are propagated faster through the thicker and myelinated axons, rather than through the thin and unmyelinated axons.