PTH_AS 2201 Lecture Notes - Lecture 4: Skeletal Muscle, Neuromuscular Junction, Cardiac Muscle
27 Apr 2016
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Document Summary
Function of muscles: produce skeletal movement, open and close body passageways; control sphincters around digestive, urinary tract, muscles of eyes, mouth, maintain posture and body position; stabilize joints; maintain muscle tone. Skeletal: pulls on the bones of the skeleton. Smooth: pushes fluids and solids along the digestive tract and regulates the diameters of small arteries. Functional syncytium: intercalated discs unite the individual cells with the heart muscle to pump in unison. One nucleus around center of elongate, spindle shaped cell. Found in walls of small arteries, wall of uterus, and intestinal tract. Receive and respond to a stimulus (nerve signal: contractility. Muscle can be extended (usually via antagonist like bicep and tricep: elasticity. Skeletal muscle fibers are very large and multinucleate. Mesoderm cells myoblasts myotube mature skeletal muscle fiber. Myofibrils muscle fiber fascicles muscle. Surrounds entire muscle, separates muscle from surrounding tissues and organs. Perimysium surrounds each fascicle and divides skeletal muscle into compartments.
