PATHOLOGY MCQ
NERVOUS SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Continuous propagation is ____
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along myelinated axons it moves at a speed of about 18-140 meters per second (18-140 mph)
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the spread of action potential down the axon
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along unmyelinated axons it moves at a speed of about 1 meter per second (2 mph)
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None of the above
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Explanation:
Detailed explanation-1: -For example, whereas unmyelinated axon conduction velocities range from about 0.5 to 10 m/s, myelinated axons can conduct at velocities up to 150 m/s.
Detailed explanation-2: -Action potential propagation along unmyelinated axons requires activation of voltage-gated sodium channels along the entire length of the axon. In sharp contrast, action potential propagation along myelinated axons requires activation of voltage-gated sodium channels only in the nodal spaces.
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