BIO SCI E112L Lecture Notes - Lecture 7: Motor Unit, Motor Neuron, Skeletal Muscle
24 Nov 2014
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1: a whole muscle is composed of numerous individual bers. 2: muscle bers are organized into motor units. Consists of a single motor neuron, the axon with all of its branches, and all of the skeletal muscle bers that those axon branches contact. 3: when a motor unit is recruited, the motor neuron res an action potential (s), which propagate down teh axon and then down each brach, causing all of the bers to contract. When a motor neuron becomes active, all of its bers contract. 4: motor units come in different sizes: a: small motor units: have few bers that are activated by the neuron b: large motor units: have many bers. 5: motor unit size varies not only between muscle, but also within each muscle. 6: the vertebrate nervous system has the ability to recruit the number of motor units appropriate to the task at hand.
