Muscular System Essay

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Name_science___________________________________Block_____Date__________________ Ch 6 The Muscular System Notes Lisa Peck Muscular System: consists of skeletal muscles and their connective tissue attachments organ- skeletal muscle consists of hundreds of muscle fibers (cells) bound tog. by connective tissue cell- muscle fibers- elongated cells largest (compared to smooth muscle) primary function is contraction: ability to shorten dep. on myofilaments muscle prefixes “myo” - muscle “mys” - muscle “sarco” - flesh 3 Muscle Types (p 178-181) 1. Skeletal Muscle- skeletal, striated, & voluntary referred to as the human body’s “muscular system” location: attach to bones or indirectly to other connective tissues or cartilage attach via tendons or aponeuroses exception: some facial muscles attach to soft tissues (oth. muscles or skin) function: create movement of bones or facial skin via contractions contraction 1. regulation: voluntary subject to conscious control via nervous system only muscle type that is voluntary 2. speed: rapidly w/ great force tire easily must rest after activity 3. no rhythmic contractions morphology: single cell elongated cylindrical shape myofiber (cell): sarcolemma- muscle cell membrane myofibrils- contractile organelles found in cytoplasm of muscle cells long tube-like have light and dark bands along length many aligned perfectly w/ in sarcolemma giving a striated appearance to cell multinucleated- nuclei and cytoplasm pushed to edge of sarcolemma by numerous myofibrils sarcoplasmic reticulum- ER of cell stores calcium (for contraction) striated- banded appearance due to alignment of bands on myofibrils myofibril bands created by arrangement of myofilaments within myofibril myofilaments- filaments composing the myofibrils two types: actin & myosin Skeletal Muscle connective tissue coverings of skeletal muscle endomysium- thin connective

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