If an axon is wrapped with glial cells, nerve impulses are propagated down this axon

a. as the action potential travels steadily down the membrane of the axon.
b. along the membranes of the surface regions of the glial cells.
c. more slowly than they would be on or via an unwrapped axon, allowing for greater control over transmission.
d. from one interruption in the myelin sheath to the next.
e. in two directions from the middle of an axon.


D; The function of one type of glial cell is to form the myelin sheath around a nerve. This speeds the transmission of the impulse down the axon because the action potential jumps from axon membrane at one gap in the sheath to the next gap instead of running down the entire length of the axon membrane (choice a). The glial cells themselves do not conduct impulses (choice b). The whole point of the myelination is to speed impulses (choice c). The direction is unchanged (choice e).

Biology & Microbiology

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Why would it be better to transplant a plant with a ball of soil surrounding its roots?

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