Question 1

Which of the following best describes the role of acetylcholinesterase at the neuromuscular junction?

Accepted Answer

It breaks down acetylcholine, preventing further stimulation of the muscle membrane.

Question 2

A sprinter experiences muscle fatigue after a short, intense race. Which metabolic process is primarily responsible for the rapid depletion of energy and accumulation of lactic acid in this scenario?

Accepted Answer

Anaerobic glycolysis

Question 3

During strenuous exercise, when oxygen supply cannot meet demand, which of the following occurs in skeletal muscle cells?

Accepted Answer

Pyruvate is converted to lactic acid

Question 4

Which statement best explains why muscle tone is important for posture?

Accepted Answer

Muscle tone maintains a constant, low-level contraction that holds the body upright.

Question 5

A patient is unable to relax their muscles after a series of rapid nerve impulses. Which physiological phenomenon is most likely occurring?

Accepted Answer

Summation leading to tetanus

Question 6

Which of the following equations correctly represents the regeneration of ATP from creatine phosphate (CP) and ADP?

Accepted Answer

$\mathrm{CP} + \mathrm{ADP} \rightarrow \mathrm{ATP} + \mathrm{Creatine}$

Question 7

Which of the following best describes the 'oxygen debt' incurred after intense exercise?

Accepted Answer

The amount of oxygen required to convert lactic acid back to glucose and restore ATP and CP levels

Question 8

If a muscle fiber is repeatedly stimulated at a high frequency, which of the following is most likely to occur?

Accepted Answer

The contractions will summate, leading to sustained contraction (tetanus).

Question 9

Which of the following adaptations would you expect in the skeletal muscles of a marathon runner after months of aerobic training?

Accepted Answer

Increased number of mitochondria and higher vascularization

Question 10

A muscle cell at rest has a low demand for ATP. Which of the following processes is most likely occurring?

Accepted Answer

Building up reserves of creatine phosphate and glycogen

Question 11

Which of the following is true regarding glycolysis in muscle cells?

Accepted Answer

It is an anaerobic process that produces 2 ATP per glucose molecule.

Question 12

What is the primary reason that lactic acid accumulates in muscle cells during intense exercise?

Accepted Answer

Pyruvate is produced faster than it can be used by mitochondria due to insufficient oxygen.

Question 13

Which of the following best explains why creatine phosphate (CP) can only power muscle contraction for about 10 seconds?

Accepted Answer

CP stores are limited and are rapidly depleted during intense activity.

Question 14

Which of the following is a direct result of calcium being pumped back into the sarcoplasmic reticulum (SR) after muscle contraction?

Accepted Answer

Cross-bridge linkages break and tropomyosin covers the active sites.

Question 15

A myogram records a delay between the stimulus and the onset of muscle contraction. What is this period called?

Accepted Answer

Latent period

Question 16

Which of the following best describes the process of recruitment in muscle contraction?

Accepted Answer

Activating additional motor units to increase the strength of contraction

Question 17

Which of the following statements about muscle fatigue is correct?

Accepted Answer

It can result from the accumulation of lactic acid, which lowers pH and impairs contraction.

Question 18

Which of the following is a correct statement about the relationship between muscle size and motor unit control?

Accepted Answer

Smaller motor units allow for finer control of muscle movements.

Question 19

Which of the following best explains why muscles can generate force up to 50 lbs per square inch of cross section?

Accepted Answer

The combined force of many muscle fibers contracting simultaneously

Question 20

After a period of intense exercise, which of the following processes helps restore muscle energy reserves?

Accepted Answer

Conversion of lactic acid back to glucose using oxygen

Muscle Physiology: Contraction, Energy, and Control

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