Chapter 10

Chapter 10 - Chapter 10 The Muscular System The Structural...

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Chapter 10 The Muscular System The Structural and Functional Organization of Muscles The Functions of Muscles 1. Muscle functions include: movement, stability, communication (facilitate speech, writing) control of body openings and passages, and heat production. Connective Tissues of a Muscle 1. Skeletal muscle cells, called muscle fibers, are each surrounded by a thin layer of areolar tissue called the endomysium. 2. Muscle fibers are grouped into bundles called fascicles, each of which is surrounded by a connective tissue sheath, the perimysium. 3. Each whole muscle is covered by yet another layer of connective tissue, the epimysium, and the epimysium grades into fascia. 4. Muscles can attach to bone directly through collagen fibers between the epimysium and periosteum or indirectly through extensions of deep fascia called tendons. General Anatomy of Skeletal Muscles 1. A muscle attachment at the stationary end is the origin; the relatively movable end is the insertion; the thicker middle region is the belly of the muscle. 2. Muscles can be classified into five types based on the orientation of their fascicles. a. Fusiform muscles are thick in the middle and tapered at each end. b. Parallel muscles are long, strap like muscles of uniform width and parallel fascicles. c. Convergent muscles are fan-shaped. d. Pennate muscles are feather-shaped and may be unipennate, bipennate or multipennate. e. Circular muscles (sphincters) surround body openings.
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Coordinated Action of Muscle Groups. 1. The movement of a muscle is its action; muscles seldom act alone. 2. The prime lover (agonist) is the muscle producing the most force. 3. A synergist is a muscle that aids the prime mover. 4. The antagonist is a muscle that opposes the prime mover; an antagonist pair of muscles acts on opposite sides of a joint. 5. A fixator is a muscle that prevents the movement of a bone. Intrinsic and Extrinsic Muscles 1. An intrinsic muscle in entirely contained within a particular region. 2. An extrinsic muscle acts upon a designated region but has its origin elsewhere. Muscle Innervation 1. Muscles of the head and neck are supplied by cranial nerves. 2. Muscles elsewhere are innervated by spinal nerves, How Muscles are Named. 1. In 1895, Latin was chosen as the official language for muscle nomenclature. Terms used in this test are English modifications of the Latin names. 2. Muscle nomenclature provides clues to location, appearances
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This note was uploaded on 04/17/2008 for the course BIOL 211 taught by Professor Wilson during the Fall '07 term at Winona.

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Chapter 10 - Chapter 10 The Muscular System The Structural...

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