KNES 385 Lecture Notes - Lecture 13: Alpha Motor Neuron, Gamma Motor Neuron, Muscle Spindle
27 Oct 2016
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The alpha motor neuron innervate the extrafusal muscle fibers that are responsible for generating force and move the body by contracting: contract the extrafusal muscle fibers- generates the emg and can then moves arms and legs. The gamma motor neurons innervate the intrafusal muscle fibers in the muscle spindles: contract the spindles, does not contract the muscle. Motor unit: an alpha motor neuron and the group of muscle fibers that it innervates. Motor unites are the smallest functional unit that the nervous system can use to control movement: every muscle fiber is innervated by exactly one motor neuron, one motor neuron can innervate many muscle fibers. Innervation ratio: the number of muscle fibers innervated by a motor neuron. Motor pool: all the motor neurons that innervate a particular muscle, the cell bodies of all the motor neurons in a motor pool are clustered together in the spinal chord. A small motor unit (mu) becomes active at a low force threshold.
