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Structure of a Skeletal Muscle quiz

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  • What structure is the functional unit of contraction in a skeletal muscle fiber?
    The sarcomere is the functional unit of contraction in a skeletal muscle fiber.
  • What term is used for the plasma membrane of a muscle fiber?
    The plasma membrane of a muscle fiber is called the sarcolemma.
  • What are thin filaments composed of?
    Thin filaments are primarily composed of the protein actin.
  • What is a motor unit composed of?
    A motor unit is composed of a motor neuron and all the muscle fibers it innervates.
  • What causes the striated appearance of skeletal muscle fibers?
    The striated appearance of skeletal muscle fibers is caused by the repeating structure of sarcomeres, composed of actin and myosin filaments.
  • What protein are the thin filaments made of?
    Thin filaments are made of the protein actin.
  • What is a transverse tubule (t‑tubule) in muscle fibers?
    B) A membrane canal that extends into the muscle fiber
  • Thin filaments are primarily composed of which protein?
    Thin filaments are primarily composed of the protein actin.
  • What is the functional contractile unit of the myofibril?
    The functional contractile unit of the myofibril is the sarcomere.
  • What part of the sarcolemma contains acetylcholine receptors?
    The part of the sarcolemma that contains acetylcholine receptors is the motor end plate.
  • What is the function of t-tubules?
    T-tubules transmit electrochemical signals deep into the muscle fiber to ensure uniform contraction.
  • What structures form a motor unit?
    A motor unit is formed by a motor neuron and the muscle fibers it innervates.
  • What are fascicles in the structure of a muscle?
    B) Fascicles are bundles of muscle fibers
  • What makes up the thick filaments?
    Thick filaments are primarily made of the protein myosin.
  • Which is found in thin filaments but is not a regulatory protein?
    Actin is found in thin filaments and is not a regulatory protein.
  • What is the function of t tubules?
    T tubules function to transmit electrochemical signals deep into the muscle fiber.
  • What protein are the thick filaments made of?
    Thick filaments are made of the protein myosin.
  • What makes up the thin filaments?
    Thin filaments are made up of the protein actin.
  • What makes up the a bands in striated muscle?
    The A bands in striated muscle are made up of overlapping thick and thin filaments.
  • What protein is a thick filament involved with contractions and contains heads to form extensions?
    Myosin is the thick filament protein involved in contractions and contains heads to form extensions.
  • The contractile portion of the thin filament is composed of what protein?
    The contractile portion of the thin filament is composed of the protein actin.
  • What is the sarcoplasmic reticulum in muscle cells?
    A structure that stores and releases calcium ions
  • Thick filaments are primarily made of which protein?
    Thick filaments are primarily made of the protein myosin.
  • What is the cause of the striated appearance of skeletal and cardiac muscle?
    The striated appearance is caused by the arrangement of actin and myosin filaments in sarcomeres.
  • Which structure in the muscle cell stores calcium?
    The sarcoplasmic reticulum stores calcium in the muscle cell.
  • What is a striation and how does it help muscle cells function?
    A striation is a pattern of alternating light and dark bands in muscle cells, aiding in contraction by organizing actin and myosin filaments.
  • What connective tissue surrounds an individual muscle cell?
    Endomysium