Muscle Contraction Theory Basics
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Questions and Answers

What is the primary function of the sarcoplasmic reticulum in muscle cells?

  • Generates action potentials
  • Anchors myosin filaments
  • Stores and releases calcium ions (correct)
  • Forms attachment sites for actin
  • Which protein serves as the attachment site on actin for calcium ions?

  • Myosin
  • Z disk
  • Tropomyosin
  • Troponin (correct)
  • In a sarcomere, where do you find the H zone?

  • Attachment site for actin
  • Center of the sarcomere (correct)
  • Contains only actin
  • Where actin and myosin overlap
  • During depolarization of a muscle fiber, what happens to the charge inside the cell?

    <p>Becomes more positive</p> Signup and view all the answers

    What is the main function of the sodium-potassium pump in muscle cells?

    <p>Maintains cell resting potential</p> Signup and view all the answers

    Where are M lines located in a sarcomere?

    <p>Where myosin are anchored</p> Signup and view all the answers

    What is the role of Acetylcholine in muscle contraction?

    <p>Stimulates muscle fiber to contract</p> Signup and view all the answers

    Where does the binding of Acetylcholine to receptor sites occur?

    <p>Synaptic cleft</p> Signup and view all the answers

    What happens when Ca2+ binds to troponin during muscle contraction?

    <p>Tropomyosin uncovers active sites on actin myofilament</p> Signup and view all the answers

    Which structure stores and releases neurotransmitters like Acetylcholine?

    <p>Synaptic vesicle</p> Signup and view all the answers

    What is the primary function of a motor neuron in muscle contraction?

    <p>Carry action potentials to muscle fibers</p> Signup and view all the answers

    What occurs when ATP binds to myosin during muscle contraction?

    <p>Myosin detaches from actin myofilaments</p> Signup and view all the answers

    What is the term for the weakest stimulus needed to produce a muscle response?

    <p>Threshold</p> Signup and view all the answers

    In which type of muscle contraction does the muscle remain contracted?

    <p>Isometric</p> Signup and view all the answers

    Which type of muscle fibers contract slowly and fatigue slowly?

    <p>Slow Twitch Fibers</p> Signup and view all the answers

    What is the function of myoglobin in muscles?

    <p>Facilitates oxygen binding in muscle</p> Signup and view all the answers

    Which type of muscle fiber contracts quickly and fatigues quickly?

    <p>Fast Twitch Fibers</p> Signup and view all the answers

    What determines the distribution of slow and fast twitch muscle fibers in humans?

    <p>Genetics</p> Signup and view all the answers

    Which muscle in the upper limb is known as the 'flexing muscle'?

    <p>Brachialis</p> Signup and view all the answers

    Which muscle is responsible for inverting the foot?

    <p>Tibialis anterior</p> Signup and view all the answers

    How many origins does the triceps muscle have?

    <p>Three</p> Signup and view all the answers

    Which muscle is located between the ribs and is responsible for elevating them?

    <p>Serratus anterior</p> Signup and view all the answers

    Which muscle in the lower leg attaches to the ankle and flexes the foot?

    <p>Soleus</p> Signup and view all the answers

    What type of muscle movement does the deltoid muscle primarily perform?

    <p>Abduction of upper limbs</p> Signup and view all the answers

    What is the role of Ca2+ in the process of muscle contraction?

    <p>Ca2+ binds to troponin causing tropomyosin to move, exposing attachment sites for myosin</p> Signup and view all the answers

    What happens when acetylcholine binds to receptor sites on Na+ channels during muscle contraction?

    <p>Na+ rushes into the postsynaptic terminal causing depolarization</p> Signup and view all the answers

    Which organelle releases stored calcium in response to Na+ entering the postsynaptic terminal during muscle contraction?

    <p>Endoplasmic reticulum</p> Signup and view all the answers

    What is the role of ATP in muscle contraction?

    <p>ATP is released from myosin heads, enabling them to bend towards the center of the sarcomere</p> Signup and view all the answers

    What causes tropomyosin to move and expose attachment sites for myosin during muscle contraction?

    <p>Ca2+ binding to troponin</p> Signup and view all the answers

    What causes muscle contraction to stop?

    <p>(Muscle contraction stops when) Acetylcholinesterase is released and Na+ channels close</p> Signup and view all the answers

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