$$32 \text{ ATP} = 1 \text{ glucose} \rightarrow \text{CO}_2 + \text{H}_2\text{O}$$

$$2 \text{ ATP} = 1 \text{ glucose} \rightarrow \text{lactic acid}$$

Question 1

Which connective tissue layer surrounds individual muscle fibers within a fascicle?

Accepted Answer

Endomysium

Question 2

During muscle contraction, which event directly follows the binding of Ca$$^{2+} to $$troponin?

Accepted Answer

Tropomyosin shifts, exposing myosin binding sites on actin

Question 3

A muscle twitch consists of three phases. Which phase is characterized by the active cross-bridge cycling and development of tension?

Accepted Answer

Period of contraction

Question 4

Which process is responsible for the rapid regeneration of ATP during the first 10-15 seconds of intense muscle activity?

Accepted Answer

Direct phosphorylation by creatine phosphate

Question 5

If a muscle is stimulated repeatedly before it has fully relaxed, what phenomenon occurs, resulting in a stronger contraction?

Accepted Answer

Temporal (wave) summation

Question 6

Which equation correctly represents the ATP yield from aerobic respiration of one glucose molecule?

Accepted Answer

$$32 	ext{ ATP} = 1 	ext{ glucose} ightarrow 	ext{CO}_2 + 	ext{H}_2	ext{O}$$

Question 7

Which type of muscle fiber is most resistant to fatigue and is primarily used for endurance activities?

Accepted Answer

Slow oxidative fibers

Question 8

A patient is unable to maintain muscle contraction during prolonged activity. Which physiological process is most likely failing?

Accepted Answer

Aerobic respiration

Question 9

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

Accepted Answer

It degrades acetylcholine, ending the action potential

Question 10

Which scenario would result in maximal muscle tension and a fused contraction plateau called tetanus?

Accepted Answer

High-frequency stimulation with no relaxation between twitches

Question 11

Which factor does NOT directly increase the force of muscle contraction?

Accepted Answer

Decreasing the overlap between actin and myosin filaments

Question 12

Which type of contraction occurs when a muscle generates force but does not change length?

Accepted Answer

Isometric contraction

Question 13

What is the primary source of ATP during light to moderate exercise lasting several hours?

Accepted Answer

Aerobic respiration

Question 14

Which of the following is a correct sequence of events in excitation-contraction coupling?

Accepted Answer

Action potential arrives, Ca$$^{2+}$$ released from SR, troponin binds Ca$$^{2+}$$, tropomyosin shifts

Question 15

Which metabolic pathway is most efficient in terms of ATP yield per glucose molecule?

Accepted Answer

Aerobic respiration

Question 16

A weightlifter experiences muscle hypertrophy after months of training. What cellular change is primarily responsible for this?

Accepted Answer

Increase in the size of muscle fibers

Question 17

Which of the following best explains why muscle fatigue occurs during prolonged, strenuous activity?

Accepted Answer

Accumulation of lactic acid and other chemical changes

Question 18

Which equation represents the ATP yield from anaerobic glycolysis of one glucose molecule?

Accepted Answer

$$2 	ext{ ATP} = 1 	ext{ glucose} ightarrow 	ext{lactic acid}$$

Question 19

Which adaptation is most likely to occur in skeletal muscle after regular endurance exercise?

Accepted Answer

Increase in mitochondria and myoglobin synthesis

Question 20

Which statement best describes the motor unit recruitment principle?

Accepted Answer

Motor units are activated in order of size, allowing graded muscle contraction

Lecture Unit 3 Ch. 9 pt 2

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