Skeletal Muscle Physiology — Nerve & Muscle Physiology

Skeletal Muscle Physiology MCQs: practice questions

Sample Skeletal Muscle Physiology multiple-choice questions from Nerve & Muscle Physiology.

1. Fast glycolytic fibers are characterized by:

   • A. High oxidative capacity and very slow contraction
   • B. Rapid contraction and relatively rapid fatigue
   • C. No myosin ATPase
   • D. No glycogen
   • E. No anaerobic metabolism

2. An action potential in a skeletal muscle fiber triggers Ca2+ release from the:

   • A. Nucleus
   • B. Sarcoplasmic reticulum
   • C. Mitochondria only
   • D. Golgi apparatus
   • E. Extracellular matrix

3. During an isotonic contraction:

   • A. Tension never develops
   • B. The sarcomere cannot shorten
   • C. Ca2+ is absent
   • D. No cross-bridges form
   • E. Muscle length changes while load is moved

4. The immediate consequence of increased cytosolic Ca2+ is:

   • A. ACh synthesis
   • B. Myosin degradation
   • C. Troponin C activation
   • D. ATP depletion to zero
   • E. T-tubule closure

5. The I band becomes shorter during contraction because:

   • A. Thick filaments shorten
   • B. T-tubules shorten
   • C. Z lines disappear
   • D. Myosin is degraded
   • E. Thin filaments move toward the center of the sarcomere

6. Which energy system can rapidly regenerate ATP during the first seconds of intense muscle activity?

7. A motor unit consists of:

8. At rest, tropomyosin primarily:

9. A sustained contraction produced by very high-frequency stimulation is called:

10. A concentric contraction occurs when the muscle:

11. During skeletal muscle contraction, the sarcomere becomes:

12. Wave summation occurs when:

13. A single brief stimulus to a skeletal muscle fiber produces a:

14. What causes myosin to detach from actin during the cross-bridge cycle?

15. Ca2+ initiates skeletal muscle contraction by binding to:

16. A muscle at excessively short sarcomere length produces less force because:

17. The power stroke occurs when the myosin head:

18. The H zone decreases during contraction because:

19. ATP is required in skeletal muscle for:

20. A muscle fiber contracts with maximal force when:

21. The functional contractile unit of a skeletal muscle fiber is the:

22. Which band remains approximately constant in length during sarcomere shortening?

23. Rigor mortis occurs because after death:

24. Increasing the number of active motor units increases whole-muscle force by:

25. An eccentric contraction occurs when the muscle:

26. The sarcoplasmic reticulum stores:

27. Which fiber type generally has the greatest oxidative capacity and fatigue resistance?

28. During an isometric contraction:

29. The T-tubule system functions mainly to:

30. The length–tension relationship refers to the effect of initial muscle length on: