EHS 385 Lecture Notes - Lecture 10: Oxidative Phosphorylation, Action Potential, Motor Unit
18 Dec 2017
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Chapter 8 lecture 10 oc skeletal muscle i. Human body contains over 600 skeletal muscles (40-50% total body weight) Functions of skeletal muscle: force production for locomotion and breathing, force production for postural support, heat production during cold stress. Muscle actions: flexors: decrease joint angle, extensors: increase joint angles. Fiber = muscle cell: long, slender, multinucleated. Fiber length varies from few millimeters (eye) to nearly 30cm (leg) 75% water, 20% protein, 5% salts, phosphates, ions, macronutrients. Tendons = tissue connecting muscle to periosteum of bone: origin= more stable bone, insertion= moving bone. Perimysium: surrounds several muscle fibers to form bundles known as fascicles. Epimysium: surrounds all bundles to form entire muscle. Play key role in muscle growth and repair: during muscle growth, satellite cells can increase number of nuclei in mature muscle fibers. Myonuclear domain: volume of cytoplasm surrounding each nucleus, each nucleus can support limited myonuclear domain. More nuclei allow for greater protein synthesis.
