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1. A 28-year-old man has been training as a distance runner for the past six years.
Compared with a sprinter, which of the following is decreased in the skeletal muscles of this athlete during resting conditions?
A. Capillary density
B. Glycolytic enzyme content C. Mitochondrial volume density D. Myoglobin content
E. Oxidative capacity ANS: A
2. A physiology experiment is conducted in which a skeletal muscle twitch is initiated using an electrical stimulator. Which factor contributes to the termination of a typical skeletal muscle twitch?
A. Calcium uptake by sarcoplasmic reticulum B. Closure of transverse tubules
C. Depletion of calcium stores from sarcoplasmic reticulum D. Exhaustion of muscle ATP stores
E. Stimulation of dihydropyridine (DHP) receptors ANS: A
3. A 24-year-old medical student goes to the local gym to lift weights. She begins by bench-pressing 100 pounds as a warm-up procedure and then gradually increases the weight. Which of the following occurs as she adds more weight?
A. Decreased frequency of motor nerve action potentials B. Decreased velocity of motor nerve action potentials C. Increased frequency of motor nerve action potentials D. Increased velocity of motor nerve action potential E. Involvement of fewer motor units
ANS: C
4. A 24-year-old woman is admitted to the emergency department after an automobile accident in which lacerations to the left wrist severed a major tendon. The severed ends of the tendon were overlapped by 6 cm to facilitate suturing and reattachment. Which of the following characteristics would be expected after six weeks compared with the pre-injured muscle? Assume that series growth of sarcomeres cannot be completed within six weeks.
Passive tension Maximal active tension A. Decrease Decrease
Test Bank B. Decrease Increase C. Increase Increase D. Increase Decrease E. No change No change ANS: D
5. During the contraction of a skeletal muscle fiber, the actin and myosin filaments slide past each other. Which of the following represent expected changes in the widths of I-bands and A-bands during the contraction process?
I-band width A-band width
A. ↑ ↔ B. ↓ ↑ C. ↓ ↓ D. ↓ ↔ E. ↔ ↑ ANS: D
6. When a person lifts a 25-pound weight, what type or types of muscle contraction are involved?
A. Isometric contraction only B. Isotonic contraction only
C. Isometric contraction followed by isotonic contraction D. Isotonic contraction followed by isometric contraction ANS: C
7. The length-tension diagram shown was obtained from a skeletal muscle with equal numbers of red and white fibers. Supramaximal tetanic stimuli were used to initiate an isometric contraction at each muscle length studied. The resting length was 20 cm. What is the maximum amount of active tension this muscle is capable of generating at a preload of 100 grams? A. 145 to 155 grams B. 25 to 35 grams C. 55 to 65 grams D. 95 to105 grams E. Cannot be determined
Copyright © 2011, 2006 by Saunders, an imprint of Elsevier Inc.
0 10 20 30 40 Length (cm) Tension (grams) 200 150
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ANS: C
8. The diagram shows the relationship between muscle tension and sarcomere length for muscle. Which point on the curve represents tension development
at a normal resting length for skeletal muscle? ANS: C
9. The diagram shows the relationship between muscle tension and sarcomere length for muscle. Which point on the curve represents tension development
at a normal resting length for cardiac muscle? ANS: B
10. A 29-year-old woman has been training as a distance runner for the past five years. Which set of changes best describes the skeletal muscles of this woman compared with a sprinter?
Capillary density Oxidative capacity Myoglobin content Fiber diameter
Copyright © 2011, 2006 by Saunders, an imprint of Elsevier Inc.
150
100 50 0 E D C B A Tension Length E D C B A Tension Length 6-3
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A. Decreased Decreased Decreased
Decreased
B. Decreased Decreased Increased
Increased
C. Increased Increased Decreased
Decreased
D. Increased Increased Increased
Decreased
E. Increased Increased Increased
Increased ANS: D
11. The length-tension diagram shown on the right was obtained from a skeletal muscle with equal numbers of red and white fibers. Supramaximal tetanic stimuli were used to initiate an isometric contraction at each muscle length studied. What are the values in grams of preload, active tension, and total tension when the muscle length is 60 cm?
Preload Active tension Total tension
A. 100 200 300 B. 100 300 200 C. 150 250 300 D. 200 100 300 E. 200 200 300 ANS: A 12. A 45-year-old man goes to the local gym to lift weights. He begins by bench-pressing 130 pounds as a warm- up procedure and then gradually increases the weight. Which of the following sets of changes occur as he adds more weight? Activation of motor units Frequency of motor nerve action potentials A. Decreased Decreased B. Decreased Increased C. Decreased No change D. Increased Decreased Copyright © 2011, 2006 by Saunders, an imprint of Elsevier Inc.
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E. Increased Increased
F. Increased No change
ANS: E
13. The skeletal muscle sarcomere normally has a
narrow range of lengths in vivo, but sarcomere length can vary greatly in vitro under non-physiological conditions. The diagram shows sarcomeres at various lengths. At which length can the sarcomere exert its maximum force during an isometric contraction?
A. 1.6 µm B. 2.1 µm C. 2.8 µm D. 3.0 µm E. 3.5 µm ANS: B
14. The diagram shows the relationship between contraction velocity and force. Which of the
following muscles is most likely to correspond to muscle number 1 shown on the diagram (assume that all muscles shown are at their normal resting
lengths). A. B.
Copyright © 2011, 2006 by Saunders, an imprint of Elsevier Inc.
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200 100 0 1.6 µm2.0 µm2.3 µm 3.7 µm 5 4 3 2 1 0 0 Force Contraction velocity 6-5
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C. D. E. ANS: E
15. The diagram shows the relationship between
contraction velocity and force. Which of the following muscles is most likely to correspond to muscle number 2 shown on the diagram (assume that all muscles shown are at their normal resting lengths)? A. B. C. D. E. ANS: D
16. The diagram shows force-velocity relationships for three
different skeletal muscles. Which of the following curves most likely correspond to glycolytic, oxidative, and mixed muscle types?
Glycolytic Oxidative Mixed
A. X Y Z B. X Z Y C. Y X Z D. Y Z X E. Z X Y F. Z Y X ANS: B 5 4 3 2 1 0 0 Force Contraction velocity 0 0 Z Y X Force Contraction velocity 6-6
muscle)? A. Blood capillaries B. Mitochondria C. Myoglobin D. Myosin ATPase E. Oxidative enzymes ANS: C
