Chapter 06 Contraction of Skeletal Muscle

Chapter 06 Contraction of Skeletal Muscle

Complete Chapter Questions And Answers
 

Sample Questions

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
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