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Muscle Contractions quiz #1 Flashcards

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Muscle Contractions quiz #1
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  • What is the cell membrane of a muscle fiber called?
    The cell membrane of a muscle fiber is called the sarcolemma.
  • What is the contractile unit of a muscle cell?
    The contractile unit of a muscle cell is the sarcomere.
  • What initiates an action potential on a muscle cell?
    An action potential on a muscle cell is initiated when a nerve releases neurotransmitters at the neuromuscular junction, leading to depolarization of the sarcolemma.
  • Which type of muscle cells have more than one nucleus?
    Skeletal muscle cells (muscle fibers) have more than one nucleus; they are multinucleated.
  • What is the name of the cell membrane of a muscle fiber?
    The cell membrane of a muscle fiber is called the sarcolemma.
  • At what location does a nerve meet a muscle cell?
    A nerve meets a muscle cell at the neuromuscular junction.
  • Which muscle cell type does not contain myofibrils?
    Smooth muscle cells do not contain myofibrils.
  • What is another name for a skeletal muscle cell?
    Another name for a skeletal muscle cell is a muscle fiber.
  • What are myofibrils in muscle cells composed of?
    Myofibrils in muscle cells are composed of repeating units called sarcomeres, which contain actin and myosin filaments.
  • What role does calcium play in muscle contraction?
    Calcium binds to troponin, which causes a conformational change in tropomyosin, exposing actin binding sites and allowing myosin to bind for muscle contraction.
  • During muscle contraction, which bands or zones of the sarcomere shorten?
    During muscle contraction, the I band and H zone of the sarcomere shorten, while the lengths of actin and myosin filaments remain unchanged.