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Essentials of Human Anatomy & Physiology Seventh Edition Elaine N. Marieb Chapter 6 The Muscular System Slides 6.1 – 6.17 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The Muscular System Named for Latin word “mus” meaning little mouse Dominant tissue in heart and the walls of other hollow organs Essential function is to shorten or contract Responsible for all body movement Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 6.1 The Muscular System Three basic muscle types are found in the body Skeletal muscle Cardiac muscle Smooth muscle Differ in cell structure, location in body and how they’re stimulated to contract Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 6.1 Characteristics of All Muscle Types Muscle cells are elongated & called fibers Contraction of muscles is due to the movement of myofilaments All muscles share some terminology Prefixes myo & mys refers to muscle Prefix sarco refers to flesh Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 6.2 Skeletal Muscle Characteristics Most are attached by tendons to bones Cells are cigar shaped & multinucleate Striated – have visible banding Largest of the muscles (up to 1 foot) Voluntary – subject to conscious control Often react involuntarily or by reflex Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 6.3 Skeletal Muscle Characteristics Can contract rapidly & with great force but tires easily Fibers (cells) are surrounded and bundled by connective tissue This allows skeletal muscle to exert great force without damaging the muscle fibers Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 6.3 Connective Tissue Wrappings of Skeletal Muscle Endomysium – around single muscle fiber Perimysium – around a fascicle (bundle) of fibers Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.1 Slide 6.4a Connective Tissue Wrappings of Skeletal Muscle 3 layers of connective tissue: endomysium, perimysium & epimysium Each layer gets thicker & tougher Figure 6.1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 6.4b Skeletal Muscle Attachments Epimysium blends into a connective tissue attachment, usually a tendon which attaches to a bone Sites of muscle attachment Bones (attached by tendon) Cartilages Connective tissue coverings of muscles Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 6.5 Smooth Muscle Characteristics Has no striations Spindle-shaped cells Single nucleus Involuntary – no conscious control Found mainly in the walls of hollow organs Figure 6.2a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 6.6 Smooth Muscle Characteristics Arranged in sheets or layers – one runs circular or around & the other runs up and down 2 layers take turns contracting & relaxing to change shape of organ and move food or waste through the digestive system, etc A slow steady contraction that goes on almost continuously Figure 6.2a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 6.6 Cardiac Muscle Characteristics Has striations Usually has a single nucleus Involuntary Found only in the heart Joined to another muscle cell at an intercalated disc Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.2b Slide 6.7 Cardiac Muscle Characteristics Muscle is arranged in spirals or figure 8s This causes the chambers to get smaller & squeeze the blood out when it contracts Contracts at a steady rate controlled by the heart’s pacemaker – nervous system can speed it up Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.2b Slide 6.7