KNES 385 Lecture Notes - Lecture 16: Alpha Motor Neuron, Motor Neuron, Motor Unit
22 Oct 2016
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Document Summary
Alpha motor neuron innervates the extrafusal muscle fibers, causing. These afferents will synapse with an alpha motor neuron. Alpha motor neuron can be affected by descending signals (from brain) Alpha motor neuron = final common path: last spot that they all converge and can affect the movement of the body via the alpha motor neuron. Motor neuron pool: all of the alpha motor neurons that innervate a single muscle: size will vary from muscle to muscle. Motor unit: alpha motor neuron and a group of muscle fibers that the alpha motor neuron innervates: alpha motor neuron innervates more than one motor neuron. Consists of thousands of muscle fibers working in parallel and organized into a smaller number of motor neurons. Principles of the motor unit organization: ratio principle, size principle. Fine need more precision and small muscle groups. Gross movements involve large muscle groups and less precision.
