Block 2 Pace Quiz Skeletal Muscle: Physiology

10 Questions | Total Attempts: 442

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Muscle Quizzes & Trivia

Questions and Answers
  • 1. 
    • A. 

      Length of the muscle.

    • B. 

      Number of motor units activated

    • C. 

      Strength of each cross-bridge interaction with actin .

    • D. 

      Maximum shortening velocity of the muscle

  • 2. 
    person beginning athletic training begins both weight training and yoga. If his skeletal muscle subsequently gains 20% more sarcomeres in length and doubles its number of sarcomeres in parallel through hypertrophy, what effect will this have on his maximum force generation?
    • A. 

      Increases 20%

    • B. 

      Increases 100%

    • C. 

      Increases 120%

    • D. 

      Increases 200%

    • E. 

      Increases 240%

  • 3. 
    Thick filaments are anchored to Z disks by what protein?
    • A. 

      Nebulin

    • B. 

      C protein

    • C. 

      Titin

    • D. 

      Alpha-actinin

    • E. 

      Myomesin

  • 4. 
    A severe laceration to a wrist completely severed a major muscle tendon . To suture the ends of the tendon together, the surgeon had to overlap the severed ends by 7.5 cm. What change if any in passive and maximum active tension would you expect?            PASSIVE                    MAXIMUM ACTIVE
    • A. 

      Increase Decrease

    • B. 

      Decrease Decrease

    • C. 

      Increase Increase

    • D. 

      Increase No change

    • E. 

      No change No change

  • 5. 
    Over the physiological (in vivo) range of muscle lengths, tension increases with length because as length increases which of the following occurs?
    • A. 

      Thin filaments overlap increasing numbers of cross-bridges.

    • B. 

      Thin filaments overlap decreasing numbers of cross-bridges

    • C. 

      There is increasing overlap of thin filaments attached to opposing Z-disks.

    • D. 

      There is decreasing overlap of thin filaments attached to opposing Z-disks

    • E. 

      There is increasing coupling of cross-bridge activation.

  • 6. 
    Assuming two skeletal muscle fibers have the same myosin ATPase activity, and both are producing an equal force, but one fiber is longer than the other one . Which of the following best describes their shortening velocities?
    • A. 

      Long fiber has a higher velocity during isotonic contraction than the short one

    • B. 

      Long fiber has a higher velocity during isometric contraction than the short one

    • C. 

      Long fiber has a lower velocity during isotonic contraction than the short one

    • D. 

      Long fiber has a lower velocity during isometric contraction than the short one

    • E. 

      Both fibers have the same velocity during isotonic contraction

  • 7. 
    Choose the correct sequence of events during excitation/contraction coupling:
    • A. 

      Action potential, calcium release, depolarization of the t-tubules, contraction, calcium reuptake

    • B. 

      Action potential, depolarization of the t-tubules, calcium release, contraction, calcium reuptake

    • C. 

      Action potential, depolarization of the t-tubules, calcium re-uptake, contraction, calcium release

    • D. 

      Action potential, calcium release, contraction, depolarization of the t-tubules, calcium reuptake

  • 8. 
    Which of the following characteristics is typical of type lIb skeletal muscle but not type I skeletal muscle?
    • A. 

      Use of ATP to provide power to myosin heads

    • B. 

      Extensive capacity for oxidative breakdown of glucose

    • C. 

      Relatively large stores of glycogen within the myocytes

    • D. 

      Myosin ATPase that is faster than that of smooth muscle

  • 9. 
    A certain skeletal muscle is at rest. What is the state of the myosin heads within that muscle's myocytes?
    • A. 

      High energy, bound to ADP and phosphate

    • B. 

      Low energy, bound to ATP

    • C. 

      High energy, with an open binding site

    • D. 

      Low energy, with an open binding site

    • E. 

      High energy, bound to ATP

  • 10. 
    An action potential propagating along the sarcolemma of a skeletal muscle cell initiates a mechanical contraction within the muscle fiber. All of the following steps are essential to initiate this increase in tension within the muscle fiber except which?
    • A. 

      Calcium binding to troponin allows myosin heads to bind to actin molecules

    • B. 

      Calcium ATPase actively transports Ca 2 + back into the sarcoplasmic reticulum (SR)

    • C. 

      Dihydropyridine (DHP) receptors tug on ryanodine receptors (RyR) causing the release of Ca 2 + through the RyR

    • D. 

      Cross-bridge cycling

    • E. 

      Membrane depolarization causes the DHP receptor to open