BIOM 3010 Lecture Notes - Lecture 3: Multinucleate, Cardiac Muscle, Motor Neuron
25 Oct 2018
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Document Summary
There are four characteristics associated with muscle tissue: Excitability: tissue can receive and respond to stimulation. Elasticity: after contracting or lengthening, tissue always wants to return to its resting state. The characteristics of muscle tissue enable it to perform some important functions, including: Guarding entrances and exists of the body (orphus) Hierarchical organization is important, allowing for graded constrictions through recruiting of different numbers of muscle fibers for various events. Big picture: skeletal muscle fibers shorten as thin filaments interact with thick filaments and sliding occurs. The trigger for contraction is the calcium ions released by the sr when the muscle fiber is stimulated by its motor neuron. Contraction is an active process; relaxation and the return to resting length is entirely passive. Isotonic contraction: muscle contraction where the muscle changes length and moves a body part. Concentric: muscle shortens as it contracts (angle of joint decreases as muscle contracts)
