PHYSIOLOGY
CENTRAL NERVOUS SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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thin, unmyelinated axon
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thin, myelinated axon
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thick, unmyelinated axon
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thick, myelinated axon
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Detailed explanation-1: -a thick, myelinated axon. The myelinated axon increases the speed of the impulse of the action potential. The thicker the sheath, the faster it can propagate.
Detailed explanation-2: -The fastest signals in our bodies are sent by larger, myelinated axons found in neurons that transmit the sense of touch or proprioception – 80-120 m/s (179-268 miles per hour).
Detailed explanation-3: -By acting as an electrical insulator, myelin greatly speeds up action potential conduction (Figure 3.14). 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-4: -Action potential propagation requires both current flow along the axon and ion fluxes across the axon membrane.