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Chapter 8 Muscular system. 8.5, 8.6, and 8.7. Muscle Types. 3 types Smooth Cardiac Skeletal. Muscle Types. Smooth Muscle Not striated Mostly involuntary Found in the linings of hollow organs, among other places
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Chapter 8 Muscular system 8.5, 8.6, and 8.7
Muscle Types • 3 types • Smooth • Cardiac • Skeletal
Muscle Types • Smooth Muscle • Not striated • Mostly involuntary • Found in the linings of hollow organs, among other places • Peristalsis = wavelike motion that pushes the contents of tubular organs forward
Muscle Types • Cardiac Muscle • Striated • Involuntary • Found in the heart • Branching cells • Intercalated discs = junctions between cell membranes that allow impulses to pass freely from cell to cell
Muscle Types • Skeletal Muscle • Striated • Mostly voluntary • Found all over the body
Origin and Insertion • Bones forming movable joints function as levers (knees, elbows, fingers, etc.) • One side of the muscle attaches to an “immovable” site and the other attaches to a movable site
Origin and Insertion • Origin = immovable end of the muscle (usually proximal) • Insertion = movable end of the muscle (usually distal) • May be more than one origin or insertion for a single muscle
Origin and Insertion • Depending on where the origin and insertions of the muscle is, it either allows for flexion or extension • Flexion = Decreases the angle between bones • Extension = Increases the angle between bones
Interaction of Skeletal Muscles • Skeletal muscles function in groups • Prime mover (agonist) = muscle that contracts to provide most of the movement • Synergists = muscles that contract and assist the prime mover • Antagonists = muscles that contract and resist movement by the prime mover or causes movement in the opposite direction • What happens if the prime mover and the antagonist both contract at the same time?