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Muscle Tissue and Contraction in Anatomy & Physiology

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Terms in this set (24)

  • Three basic types of muscle tissue

    Skeletal: voluntary, striated, multinucleated; Cardiac: involuntary, striated, branched, intercalated discs; Smooth: involuntary, non-striated, spindle-shaped cells.

  • Four important functions of muscle tissue

    Movement, posture maintenance, joint stabilization, and heat generation.

  • Gross structure of a skeletal muscle

    Composed of muscle fibers bundled into fascicles, surrounded by connective tissues: endomysium, perimysium, and epimysium.

  • Microscopic structure of myofibrils

    Myofibrils are rod-like units within muscle fibers containing repeating sarcomeres, the contractile units made of actin and myosin filaments.

  • Role of sarcoplasmic reticulum in muscle fibers

    The sarcoplasmic reticulum stores and releases calcium ions essential for muscle contraction.

  • Function of T tubules in skeletal muscle fibers

    T tubules conduct electrical impulses deep into the muscle fiber to trigger calcium release from the sarcoplasmic reticulum.

  • Sliding filament model of muscle contraction

    Actin filaments slide over myosin filaments, shortening sarcomeres and contracting the muscle.

  • Events at the neuromuscular junction to stimulate contraction

    Motor neuron releases acetylcholine, which binds to receptors on the muscle fiber, triggering an action potential.

  • Excitation-contraction coupling process

    Action potential travels along T tubules, causing calcium release from sarcoplasmic reticulum, enabling cross bridge formation.

  • Steps of a cross bridge cycle

    Cross bridge formation, power stroke, detachment, and re-cocking of myosin head using ATP.

  • Definition of motor unit

    A motor neuron and all the muscle fibers it innervates.

  • Definition of muscle twitch and its three phases

    A single muscle fiber contraction with phases: latent (delay), contraction, and relaxation.

  • How smooth, graded contractions are produced

    By varying the number of motor units activated and their firing frequency.

  • Difference between isometric and isotonic contractions

    Isometric: muscle tension without length change; Isotonic: muscle changes length with constant tension.

  • Three ways ATP is regenerated during muscle contraction

    Creatine phosphate, anaerobic glycolysis, and aerobic respiration.

  • Definition of EPOC and muscle fatigue

    EPOC: excess post-exercise oxygen consumption; fatigue: decline in muscle's ability to generate force.

  • Possible causes of muscle fatigue

    ATP depletion, lactic acid buildup, ionic imbalances, and central nervous system fatigue.

  • Effects of aerobic vs resistance exercise on skeletal muscles

    Aerobic: increases endurance and mitochondria; resistance: increases muscle size and strength.

  • Functions of prime movers, antagonists, and synergists

    Prime movers produce main movement; antagonists oppose; synergists assist prime movers.

  • How muscle position relative to a joint affects its action

    Muscle location determines the direction and type of movement it produces at the joint.

  • Criteria used in naming muscles

    Location, shape, size, direction of fibers, number of origins, origin/insertion, and action (e.g., biceps brachii).

  • Common patterns of fascicle arrangement and power generation

    Parallel (speed), pennate (power), convergent, circular; pennate generate more force.

  • Definition of lever and mechanical advantage

    A lever is a rigid bar that moves on a fulcrum; mechanical advantage means less effort needed to move a load.

  • Three types of lever systems and their arrangements

    First-class: fulcrum between effort and load; second-class: load between fulcrum and effort; third-class: effort between fulcrum and load.