PSY-P 337 Study Guide - Midterm Guide: Extrafusal Muscle Fiber, Gamma Motor Neuron, Alpha Motor Neuron
21 Feb 2017
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Document Summary
Motor unit: neuron innervating power-producing, extrafusal muscle fiber. Surface emg: crude measurement, electrodes on surface of skin. Reciprocal inhibition: process of muscles on one side of joint relaxing to accommodate contraction on other side of joint or inhibition of agnonist from antagonist muscle. Joints are controlled by opposing sets of muscles(extensor/flexor) which must work in synchrony for smooth movement. When muscle spindle is stretched and stretch reflex is activated the opposing muscle group must inhibit to prevent it from working against resulting contraction (inhibitory interneuron from spinal cord) Recurrent inhibition: inhibition that prevents muscles from firing too rapidly, kind of like a refractory period. Motor neurons: innervating power, produces extrafusal muscle fiber (alpha/ gamma) Spinal cord motor nuclei innervate individual muscles, clustered in longitudinal pools w/i spinal cord. In medial lateral axis according to function: medial nuclei: mediated across several segments via long propriospinal neurons, lateral nuclei: innervate distal musculature, interconnection by short propriospinal neurons.
