10.9: Chapter Review Questions

Multiple-Choice Section

• Use the end‑of‑chapter multiple‑choice section as a regular self‑check tool, not just before exams.
• Read each item carefully, think about what is really being tested (concept, definition, application, or calculation), and choose the option (A, B, C, or D) that best reflects what you have learned in this chapter.
  • After you read through the chapter, attempt all items without looking at your notes; then return to the chapter to review any you missed or felt unsure about.
  • Afterward, explain to yourself why the correct option is right and why the others are not. Finally, repeat the multiple‑choice section a few days later to see what you truly remember and understand.
• Students who consistently use these prompts in this way typically perform better across the course because they turn reading into active practice.

1. Muscle tissue that has a striped or banded appearance when viewed under the microscope is described as which type?
   A. Elastic
   B. Nonstriated
   C. Excitable
   D. Striated

2. Which ion directly triggers contraction by binding to the regulatory protein on the thin filament?
   A. Sodium (Na⁺)
   B. Calcium (Ca²⁺)
   C. Potassium (K⁺)
   D. Chloride (Cl⁻)

3. Which of the following properties is not shared by skeletal, cardiac, and smooth muscle tissues?
   A. Excitability
   B. The need for ATP to contract
   C. Use of regulatory proteins that block actin–myosin interaction at rest
   D. Elasticity

4. Which sequence correctly lists structural components of skeletal muscle from smallest to largest?
   A. Fascicle, filament, muscle fiber, myofibril
   B. Filament, myofibril, muscle fiber, fascicle
   C. Muscle fiber, fascicle, filament, myofibril
   D. Myofibril, muscle fiber, filament, fascicle

5. During depolarization of the sarcolemma, which electrical change occurs?
   A. The inside of the membrane becomes less negative as sodium ions enter the cell.
   B. The outside of the membrane becomes less negative as sodium ions enter the cell.
   C. The inside of the membrane becomes more negative as sodium ions enter the cell.
   D. The sarcolemma completely loses any electrical charge on both sides.

6. In a relaxed skeletal muscle fiber, which protein directly blocks the myosin‑binding sites on actin?
   A. Titin
   B. Troponin
   C. Myoglobin
   D. Tropomyosin

7. According to the sliding filament model, when do the myosin‑binding sites on actin become exposed?
   A. When creatine phosphate levels rise
   B. When ATP levels rise
   C. When acetylcholine levels rise in the synaptic cleft
   D. When calcium ion concentration rises in the sarcoplasm

8. The plasma membrane of a skeletal muscle fiber is known by which term?
   A. Myofibril
   B. Sarcolemma
   C. Sarcoplasm
   D. Myofilament

9. What primary event leads to relaxation of a skeletal muscle fiber after contraction?
   A. Calcium ions are actively transported out of the sarcoplasmic reticulum into the sarcoplasm.
   B. Calcium ions diffuse out of the sarcoplasmic reticulum into the sarcoplasm.
   C. Calcium ions are actively transported from the sarcoplasm back into the sarcoplasmic reticulum.
   D. Calcium ions diffuse from the sarcoplasm back into the sarcoplasmic reticulum.

10. During the cross‑bridge cycle, what must happen for the myosin head to detach from actin?
    A. The myosin head binds to ADP only.
    B. The myosin head binds to ATP.
    C. Calcium ions bind directly to the myosin head.
    D. Calcium ions bind directly to actin.

11. Thin and thick filaments are organized into repeating functional units along the length of a myofibril. What are these units called?
    A. Myofibrils
    B. Myofilaments
    C. T‑tubules
    D. Sarcomeres

12. During a single muscle twitch, in which phase is the tension produced by the muscle fiber at its maximum?
    A. Resting phase
    B. Repolarization phase
    C. Contraction phase
    D. Relaxation phase

13. Which of the following best explains the primary cause of skeletal muscle fatigue during intense, prolonged activity?
    A. Buildup of ATP and lactic acid
    B. Exhaustion of energy reserves and buildup of lactic acid
    C. Buildup of ATP and pyruvic acid
    D. Exhaustion of energy reserves and buildup of pyruvic acid

14. Compared with a marathon runner, why does a 100‑m sprinter typically experience muscle fatigue sooner during maximal effort?
    A. Greater reliance on anaerobic metabolism in the sprinter’s active muscles
    B. Greater reliance on anaerobic metabolism in the marathon runner’s active muscles
    C. Greater reliance on aerobic metabolism in the sprinter’s active muscles
    D. Greater reliance on glycolysis in the marathon runner’s active muscles

15. Which chemical feature of creatine phosphate allows it to serve as a rapid energy reserve for skeletal muscle?
    A. ATPase activity in the creatine molecule
    B. High‑energy phosphate bonds that can regenerate ATP
    C. High‑energy carbon–carbon bonds
    D. High‑energy hydrogen bonds

16. A drug prevents muscle cells from regenerating ATP from ADP and inorganic phosphate. Assuming no other direct effect, how will skeletal muscle cells most immediately respond?
    A. They will absorb ATP directly from the bloodstream in sufficient amounts.
    B. They will use ADP as an alternative direct energy source for contraction.
    C. They will quickly lose the ability to maintain cross‑bridge cycling and stop contracting.
    D. They will continue contracting normally because glycogen is still present.

17. The muscles of an elite sprinter are most likely to have which approximate distribution of fiber types?
    A. 80 percent fast‑twitch fibers and 20 percent slow‑twitch fibers
    B. 20 percent fast‑twitch fibers and 80 percent slow‑twitch fibers
    C. 50 percent fast‑twitch fibers and 50 percent slow‑twitch fibers
    D. 40 percent fast‑twitch fibers and 60 percent slow‑twitch fibers

18. The muscles of an elite marathon runner are most likely to have which approximate distribution of fiber types?
    A. 80 percent fast‑twitch fibers and 20 percent slow‑twitch fibers
    B. 20 percent fast‑twitch fibers and 80 percent slow‑twitch fibers
    C. 50 percent fast‑twitch fibers and 50 percent slow‑twitch fibers
    D. 40 percent fast‑twitch fibers and 60 percent slow‑twitch fibers

19. Which statement about fast (type II) skeletal muscle fibers is accurate?
    A. Fast fibers have a small diameter.
    B. Fast fibers contain loosely packed myofibrils.
    C. Fast fibers have large glycogen reserves.
    D. Fast fibers contain many more mitochondria than slow fibers.

20. Which statement about slow (type I) skeletal muscle fibers is false?
    A. Slow fibers have only a small network of capillaries.
    B. Slow fibers contain the oxygen‑binding pigment myoglobin.
    C. Slow fibers contain a large number of mitochondria.
    D. Slow fibers can maintain contractions for extended periods.

21. Which feature is present in cardiac muscle cells but absent in skeletal muscle fibers?
    A. Striations formed by sarcomeres
    B. Dependence on aerobic metabolism
    C. Myofibrils made of actin and myosin
    D. Intercalated discs connecting adjacent cells

22. If cardiac muscle cells were prevented from carrying out aerobic metabolism for an extended period, what would ultimately occur?
    A. They would rely exclusively on glycolysis and maintain normal contraction indefinitely.
    B. They would synthesize sufficient ATP using only stored creatine phosphate.
    C. They would eventually be unable to produce adequate ATP and stop contracting.
    D. They would begin to contract more rapidly to compensate.

23. Which statement best distinguishes smooth muscle from both skeletal and cardiac muscle?
    A. Smooth muscle lacks myofibrils arranged into visible striations.
    B. Smooth muscle is always under voluntary control.
    C. Smooth muscle lacks myosin molecules.
    D. Smooth muscle lacks actin filaments.

24. Which of the following accurately describes a property of smooth muscle cells?
    A. They are highly resistant to fatigue and can sustain contractions for long periods.
    B. They have a very rapid onset of contraction similar to fast‑twitch skeletal fibers.
    C. They are capable of producing tetanic contractions similar to skeletal muscle.
    D. They rely primarily on anaerobic metabolism during normal activity.

25. From which embryonic cell type do skeletal muscle fibers ultimately develop?
    A. Ganglion cells
    B. Myotube cells
    C. Myoblast cells
    D. Satellite cells

26. Which cell type is most important for the repair and partial regeneration of injured skeletal muscle fibers in adults?
    A. Ganglion cells
    B. Myotube cells
    C. Myoblast cells in the embryo only
    D. Satellite cells adjacent to mature fibers

27. During excitation–contraction coupling in skeletal muscle, what is the primary role of the transverse (T) tubules?
    A. To store calcium for release during contraction
    B. To propagate the action potential into the interior of the muscle fiber
    C. To synthesize ATP during contraction
    D. To anchor thick and thin filaments at the Z disc

28. In an isometric contraction of a skeletal muscle, what happens at the level of the sarcomere?
    A. Sarcomeres shorten and overall muscle length decreases.
    B. Sarcomeres lengthen while muscle tension remains constant.
    C. Cross‑bridge cycling occurs and tension develops, but overall muscle length does not change.
    D. No cross‑bridges form and no tension is produced.

29. When a skeletal muscle is stimulated at a frequency that does not allow full relaxation between twitches, which phenomenon occurs?
    A. Twitch summation leading to incomplete tetanus
    B. Single twitch with no change in tension
    C. Complete tetanus with zero tension
    D. Muscle fatigue without any change in stimulation frequency

30. Which change would most likely increase the force of contraction produced by a whole skeletal muscle in vivo?
    A. Decreasing the number of active motor units while keeping frequency constant
    B. Increasing the frequency of action potentials in motor neurons to produce tetanus
    C. Decreasing the initial length of the muscle to well below its optimal length
    D. Preventing recruitment of additional motor units during stronger efforts