Unformatted text preview: is an efferent--i.e. it is entirely motor in function and produces the contraction of the intrafusal fibers. I would argue that the functions are quite different. One (the afferent) senses stretch, while the other contracts the fibers in the spindle ensuring that the spindle continues to respond to muscle stretch if the extrafusal fibers are contracted to shorten the muscle. Conversely, a decrease in the activity of the gamma motor neuron will decrease the contraction of the intrafusal fibers and allow the spindle to lengthen if the extrafusal fibers are also less active....
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- Spring '08
- Physiology, Intrafusal Fibers, gamma motor