ENS 307 Lecture Notes - Lecture 12: Endoplasmic Reticulum, Muscle Fatigue, Myocyte
23 Mar 2020
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Document Summary
May be associated with physical weakness or difficulty in performing cognitive tasks. Refer to activity dependent changes of the muscles or nervous system when there is a decrease in motor output. Exercise-related decrease in the ability of the muscle to generate force or output. Not all sorts of fatigue leads to complete impairment of motor performance. You don"t need max force output all the time. Myosin attaches to actin triggering the shortening of the sarcomere (sliding filament model) Atp also helps pumping back na and k ions back to where they belong. Major contributors likely to be within the muscle fibers. The muscle fibers no longer respond to the nerve action potential. With repeated stimulation extracellular accumulation of k+ decreased release of calcium ions from the sarcoplasmic reticulum alter kinetics of cross-bridge cycle. Sending action potentials to more motor units. More motor neurons stimulating more muscle fibers. Small fibers medium fibers large fibers.
