ANAT 025 Lecture Notes - Lecture 8: Myocyte, Bloodborne, Glycogen
25 May 2020
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Constant, slightly contracted state of all muscles. Groups of motor units are alternatively activated in response to input from stretch receptors in muscles. Keeps muscles firm, healthy, and ready to respond. Atp supplies the energy needed for the muscle fiber to: Pump na+ out of and k+ back into cell after excitation-contraction coupling. Available stores of atp depleted in 4 6 seconds. Atp is the only source of energy for contractile activities; therefore it must be regenerated quickly. Anaerobic pathway: glycolysis and lactic acid formation. Atp can be generated by breaking down and using energy stored in glucose. Glucose is broken into 2 pyruvic acid molecules. 2 atp are generated for each glucose broken down. Low oxygen levels prevent pyruvic acid from entering aerobic respiration phase. Normally, pyruvic acid enters mitochondria to start aerobic respiration phase; however, at high intensity activity, oxygen is not available. Bulging muscles compress blood vessels, impairing oxygen delivery.
