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Bell Work. What do muscles do for the body? What does the word voluntary mean? What is a tendon? What is meant by perpendicular? Where would we find cardiac muscle ? What is a striation? What does endo - mean again?. Muscle Types. There are three muscle types: Skeletal Cardiac Smooth
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Bell Work • What do muscles do for the body? • What does the word voluntary mean? • What is a tendon? • What is meant by perpendicular? • Where would we find cardiac muscle? • What is a striation? • What does endo- mean again?
Muscle Types • There are three muscle types: • Skeletal • Cardiac • Smooth • The ability of a muscle to shorten depends on two types of myofilaments • Skeletal and smooth are elongatedand therefore are referred to as musclefibers • Anytime you see the following prefixes, you are dealing with a muscle • Myo- • Mys- • Sarco-
Skeletal Muscle • Composed of skeletal muscle fibers • Also known as striated (striped) muscle and voluntary muscle • They are cigar shaped, multinucleated, and large (some are nearly a foot in length) • Can contract rapidly with great force, but tireeasily and need to rest after periods of activity
Skeletal Muscle Parts • Endomysium – delicate connective tissue sheath that surrounds the muscle • Fascicle – a bundle of muscle fibers • Perimysium – Courser membrane that covers the fascicle. • Epimysium – An even tougher cover that surrounds multiple fascicles. This covers the entire muscle and blends into either a • Tendon – strong, cordlike material that connects the muscle to bones • Aponeuroses – Attaches muscle indirectly to bone, cartilage, or other connective tissues
Smooth Muscle • No striations • Involuntary • Spindle shaped with a single nucleus, arranged in sheets • Usually arranged in two layers running in different directions (think perpendicular) • Found in the walls of hollowvisceral organs (stomach, bladder, respiratorypassages) and is used to propel substances along the tract
Cardiac Muscle • Found only in the heart • It is striated, but involuntary • They are branching cells joined at special junctions called intercalateddiscs • Cushioned by small amounts of soft connective tissue and arranged in spiral or figure 8 shaped bundles • Usually controlled by an internalpacemaker, but can also be influenced hormones and the nervous system
Muscle Function • Producing Movement • Maintain Posture • Stabilizing Joints • Generating Heat