Neural Control of Muscle Contraction

Up to this point, we have been concerned with the physiology of muscle at the level of single muscle fibers. We have come to some understanding of the mechanisms involved in the linkage between an action potential in a presyn-aptic motor neuron and the contraction of the postsynaptic muscle cell. We saw that the motor neuron depolarizes the muscle fiber, causing an action potential that, in turn, triggers the all-or-none contraction of the fiber. At this point, we will step back a bit from this cellular perspective and look at the functioning of a skeletal muscle as a whole. We will consider how the all-or-none twitches of single muscle fibers are integrated into the smooth, graded movements we know our muscles are capable of making.

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