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Ch 9 Skeletal Muscle Tissue and Organization

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Terms in this set (20)

  • What are the three types of muscle tissue?

    Skeletal muscle moves the body by pulling on bones, cardiac muscle pushes blood through the circulatory system, and smooth muscle moves fluids and solids through digestive and other systems.

  • What are the four basic properties shared by all muscle tissues?

    Excitability, contractility, extensibility, and elasticity.

  • What is the function of skeletal muscles?

    Produce skeletal movement, maintain posture, support soft tissues, regulate material entry/exit, and maintain body temperature.

  • What are the layers of connective tissue in skeletal muscle from outermost to innermost?

    Epimysium surrounds the whole muscle, perimysium surrounds muscle fascicles, and endomysium surrounds individual muscle fibers.

  • What is a muscle fascicle?

    A bundle of muscle fibers surrounded by perimysium.

  • What is a muscle fiber?

    A single muscle cell surrounded by endomysium and containing myofibrils.

  • What is a sarcomere?

    The functional contractile unit of a myofibril, defined by the area between two Z lines.

  • What are the main components of a sarcomere?

    Thick filaments (myosin), thin filaments (actin), Z lines, M line, H band, I band, and zone of overlap.

  • What happens to the sarcomere during muscle contraction according to the sliding filament theory?

    The H band and I band get smaller, the zone of overlap gets larger, Z lines move closer, and the A band stays the same width.

  • What triggers muscle contraction at the molecular level?

    Calcium ions bind to troponin, causing tropomyosin to move and expose active sites on actin for myosin binding.

  • What role does ATP play in muscle contraction?

    ATP is required for myosin heads to detach from actin and to power the contraction cycle.

  • What is the neuromuscular synapse?

    The junction where a motor neuron communicates with a muscle fiber to initiate contraction.

  • What is muscle tone?

    Resting tension in skeletal muscles produced by continuous, low-level contraction of some motor units.

  • What changes occur in muscle fibers during hypertrophy?

    Increased mitochondria, glycolytic enzymes, glycogen reserves, and myofibrils, leading to muscle enlargement.

  • What are the characteristics of fast skeletal muscle fibers?

    Large diameter, many myofibrils, large glycogen reserves, few mitochondria, fatigue easily, and contract quickly.

  • What are the characteristics of slow skeletal muscle fibers?

    Smaller diameter, abundant mitochondria, use aerobic metabolism, rich capillary supply, contain myoglobin, and resist fatigue.

  • What are intermediate muscle fibers?

    Fibers with properties between fast and slow fibers; contract speed faster than slow but slower than fast, more mitochondria, and greater fatigue resistance than fast fibers.

  • What is the difference between origin and insertion in muscle anatomy?

    Origin is the stationary attachment point; insertion is the movable attachment point of a muscle.

  • What are the three types of muscle actions?

    Prime movers (agonists) produce a movement, synergists assist the prime mover, and antagonists oppose the prime mover.

  • What are the three classes of levers in the muscular system?

    First-class levers, second-class levers (force magnified), and third-class levers (speed and distance increased).