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Muscular System and Muscle Tissue - Anatomy & Physiology

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이 집합의 용어 (20)

  • What is the primary function of muscle tissue?
    Muscle tissue is specialized to contract to create movement by converting chemical energy to mechanical energy.
  • Name the 3 types of muscle tissue in the human body.
    Skeletal muscle, cardiac muscle, and smooth muscle.
  • How do skeletal, cardiac, and smooth muscles differ in striation and control?
    Skeletal muscle is striated and voluntary, cardiac muscle is striated and involuntary, smooth muscle is non-striated and involuntary.
  • What are the four key properties of muscle tissue?
    Contractility (forceful shortening), extensibility (ability to stretch), elasticity (return to original length), and excitability (respond to stimuli).
  • What is a muscle fiber?
    A muscle fiber is a long, multinucleated muscle cell surrounded by endomysium.
  • What is a fascicle in muscle tissue?
    A fascicle is a bundle of muscle fibers surrounded by perimysium.
  • What connective tissue surrounds an entire muscle?
    The entire muscle is surrounded by epimysium.
  • What are myofilaments and what are the two main types?
    Myofilaments are protein filaments within myofibrils; the two main types are actin (thin) and myosin (thick) filaments.
  • What is the sarcomere?
    The sarcomere is the smallest contractile unit of a muscle fiber, composed of overlapping actin and myosin filaments.
  • Describe the sliding filament theory of muscle contraction.
    During contraction, myosin heads pull actin filaments toward the center of the sarcomere, shortening the muscle without changing filament length.
  • What role does calcium play in muscle contraction?
    Calcium binds to troponin, causing tropomyosin to move and expose myosin binding sites on actin, enabling contraction.
  • What is the function of tropomyosin in muscle fibers?
    Tropomyosin blocks myosin binding sites on actin when the muscle is relaxed, preventing contraction.
  • What is the role of ATP in the cross-bridge cycle?
    ATP binds to myosin, causing it to release actin, then is hydrolyzed to cock the myosin head for the next power stroke.
  • What happens during the power stroke in muscle contraction?
    The myosin head pivots, pulling the actin filament toward the sarcomere center, shortening the muscle.
  • What is the neuromuscular junction?
    The neuromuscular junction is the synapse where a motor neuron communicates with a muscle fiber using acetylcholine.
  • What initiates an action potential in a muscle fiber?
    Acetylcholine released from the motor neuron binds to receptors on the sarcolemma, triggering an action potential.
  • What is excitation-contraction coupling?
    The process where an action potential travels along the sarcolemma and T-tubules, causing calcium release and muscle contraction.
  • What are the main bands and lines in a sarcomere?
    A band contains thick and thin filaments, I band contains thin filaments only, H zone contains thick filaments only, Z disc marks sarcomere boundaries, and M line is the center of thick filaments.
  • How do the A band, I band, and H zone change during muscle contraction?
    The A band stays the same length, the I band and H zone shorten as filaments slide past each other.
  • What is the function of the sarcoplasmic reticulum in muscle fibers?
    The sarcoplasmic reticulum stores and releases calcium ions to trigger muscle contraction.