Kinesiology 2230A/B Lecture Notes - Electrical Synapse, Stretch Reflex, Myofibril

• School: Western University
• Department: Kinesiology
• Course: Kinesiology 2230A/B
• Professor: Glen Belfry

Document Summary

Recall: scaffolding proteins help muscles keep their shape, binding sights for proteins involved in signaling cascades. Give the muscle strength, allow it to shorten. Muscular dystrophy is a dissolving of the proteins involved in distrophin (which connects actin to the sarcolemma) and the muscle is unable to shorten. Over time the membranes disintegrate and it leads to loss of function. Z line: at the end of the sarcomere. Initiation of muscle contraction: alpha-motor neuron is stimulated and propagates the action potential along the nerve. Depolarization (where there is a movement of charge across cell membrane) moves along nerve: action potential crosses neuromuscular junction. You can have one nerve stimulating multiple muscle fibres: action potential enters muscle and causes calcium release. Action potential: rapid and sustained depolarization of the nerve membrane: membrane must first reach threshold before action potential can occur. There has to be a change in polarity that reaches a certain threshold.