lecture 2 part 2
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Questions and Answers

Which characteristic of skeletal muscle makes up approximately 40% of body mass?

  • Energy transformation to generate force
  • Heat production
  • Protein storage and metabolism (correct)
  • Unique set of properties

    • What is one of the functions of skeletal muscle besides generating force through contraction?

  • Insulation against cold (correct)
  • Producing sound waves
  • Supporting digestion
  • Storing electrolytes

    • How does the intrinsic muscle structure influence muscle force output?

  • By affecting the amount of tension the muscle can generate (correct)
  • By determining the type of movements the muscle can perform
  • By controlling the speed of muscle contraction
  • By regulating blood flow within the muscle

    • What is the primary function of the motor neuron in relation to skeletal muscle?

    <p>Generating electrical impulses for muscle contraction</p> Signup and view all the answers

    How does the neuromuscular junction contribute to excitation-contraction coupling in skeletal muscle?

    <p>By transmitting signals from the motor neuron to the muscle fiber</p> Signup and view all the answers

    What is the term used to describe the invaginations of the sarcolemma at regular intervals in the skeletal muscle structure?

    <p>T-tubules</p> Signup and view all the answers

    Which of the following is not a component of the close interaction in the skeletal muscle structure?

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

    Which muscle architecture has a greater overall force capacity due to a larger Physiological CSA?

    <p>Multipennate muscle</p> Signup and view all the answers

    What does the correction factor cosβ account for in the force applied to the tendon in muscles?

    <p>Angle of attachment to tendon</p> Signup and view all the answers

    Which component contributes to the physical proximity in the skeletal muscle structure by providing calcium regulatory sites for contraction?

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

    What is the term used to describe muscles that have fibers running at an oblique angle to the tendon?

    <p>Pennated muscles</p> Signup and view all the answers

    What is the function of tropomyosin in muscle contraction?

    <p>Regulates the exposure of the myosin binding site for crossbridge cycling</p> Signup and view all the answers

    Which structure in the sarcomere serves as an anchor for regulatory proteins?

    <p>Z line</p> Signup and view all the answers

    What is the primary function of titin in muscle structure?

    <p>Anchors thin filaments to the Z-line</p> Signup and view all the answers

    Which component is considered the functional unit of skeletal muscle?

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

    What is the role of troponin in muscle contraction?

    <p>Regulates the exposure of the myosin binding site for crossbridge cycling</p> Signup and view all the answers

    Where do regulatory proteins troponin and tropomyosin primarily act within the sarcomere?

    <p><em>Z line</em></p> Signup and view all the answers

    What is the relationship between pennation angle and P-CSA in muscles?

    <p>Greater pennation angle leads to greater P-CSA</p> Signup and view all the answers

    What is the trade-off associated with having a greater pennation angle in muscles?

    <p>Smaller fascicle length</p> Signup and view all the answers

    How does muscle fibre type composition affect muscle contraction?

    <p>Faster contraction speed with a higher proportion of fast-twitch fibres</p> Signup and view all the answers

    What is the primary determinant of muscle force output according to the text?

    <p>Cross-sectional area (CSA)</p> Signup and view all the answers

    How are muscle fibre types classified in humans according to the text?

    <p>I, IIA, and IIX</p> Signup and view all the answers

    How does a change in muscle length impact fibre length?

    <p>Greater change in fibre length than muscle length</p> Signup and view all the answers

    Why do variations in muscle shapes and architecture, such as fusiform, non-pennate, and multipennate muscles exist?

    <p>To optimize muscle function based on different force and shortening requirements.</p> Signup and view all the answers

    How does the small loss of force per fiber in muscles with greater pennation angle translate into an advantage?

    <p>It results in a significant increase in packing density and overall greater force potential.</p> Signup and view all the answers

    What is the primary function of the motor neuron in relation to skeletal muscle?

    <p>The primary function of the motor neuron is to transmit neural signals from the central nervous system to the muscle fibers, initiating muscle contraction.</p> Signup and view all the answers

    What is the role of regulatory proteins troponin and tropomyosin in the sarcomere?

    <p>Regulate the exposure of the myosin binding site for crossbridge cycling in response to calcium.</p> Signup and view all the answers

    How do thick and thin filaments interact to generate force in the sarcomere?

    <p>Through the crossbridge force generation mechanism.</p> Signup and view all the answers

    What is the significance of the Z line in the sarcomere structure?

    <p>It serves as an anchor for many regulatory proteins, notably thin filaments.</p> Signup and view all the answers

    What is the primary function of titin in the muscle structure?

    <p>Titin serves as an anchor, linking the thick filaments to the Z-line and providing elasticity to the sarcomere.</p> Signup and view all the answers

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