KINE 3P94 Lecture Notes - Lecture 3: Alpha Motor Neuron, Lower Motor Neuron, Anterior Grey Column

• School: Brock University
• Department: Physical Education and Kinesiology
• Course: KINE 3P94
• Professor: Jae Patterson

Document Summary

Pekn 3p94 lec 3: monday, september 23, 13. Extrafusal fibers are innervated by the alpha motor neuron. A-mn can diverge and innervate more than 1 muscle fiber, but 1 muscle fiber can only be activated by one motor neuron. Upper motor neurons= brain to spinal cord. If the a-mn is not activated, the muscle is relaxed. Muscle fiber types- fast twitch, slow twitch. No mixing fiber types within a motor unit. However, within the muscle there are different types of motor units composed of different muscle fiber types. The ventral horn is composed only of cell bodies of alpha motor neurons. Flexor-extensor rule: extensor muscles have motor neurons that lie on the front part of the ventral horn, flexor muscles have motor neurons that lie on the dorsal part of the ventral horn. ** know the diffs between motor unit and motor neuron pool. The more fibers that are activated by a motor neuron means more force is generated.