HISTOLOGY
NERVOUS TISSUE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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only occur in myelinated fibers
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are the same as graded potentials
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vary in size depending on the strength of the initial stimulus
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allow an impulse to travel over both long and short distances.
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Detailed explanation-1: -Action potentials (APs) are all-or-nothing, nondecremental, electrical potentials that allow an electrical signal to travel for very long distances (a meter or more) and trigger neurotransmitter release through electrochemical coupling (excitation-secretion coupling).
Detailed explanation-2: -The regenerative properties of Na+ channel opening allow action potentials to propagate in an all-or-none fashion by acting as a booster at each point along the axon, thus ensuring the long-distance transmission of electrical signals.
Detailed explanation-3: -While typically thought of as being unidirectional, it is not uncommon for axonal propagation of action potentials to happen in both directions. This is the case because action potentials can be initiated at multiple “ectopic” positions along the axon.