Question 1

Which of the following best describes the function of the sarcoplasmic reticulum in skeletal muscle contraction?

Accepted Answer

It stores and releases calcium ions ($$\mathrm{Ca$$^{2+}$$}) $$necessary for muscle contraction.

Question 2

During the cross-bridge cycle, what is the immediate consequence if ATP is unavailable?

Accepted Answer

Myosin heads remain attached to actin, resulting in rigor mortis.

Question 3

A patient is given a drug that blocks the release of acetylcholine at the neuromuscular junction. What is the most likely effect?

Accepted Answer

Muscle contraction will not occur because the action potential cannot be transmitted to the muscle fiber.

Question 4

Which connective tissue layer surrounds individual muscle fibers?

Accepted Answer

Endomysium

Question 5

In the sliding filament theory, which bands of the sarcomere change length during contraction?

Accepted Answer

The I band and H zone decrease in length, while the A band remains unchanged.

Question 6

Which equation best represents the regeneration of ATP from creatine phosphate during muscle contraction?

Accepted Answer

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

Question 7

A muscle is stimulated repeatedly at a frequency that does not allow complete relaxation between stimuli. What is the resulting phenomenon called?

Accepted Answer

Incomplete tetanus

Question 8

Which of the following best explains why oxygen debt develops after intense exercise?

Accepted Answer

Oxygen is required to restore ATP, remove lactic acid, and replenish creatine phosphate stores.

Question 9

Which type of muscle contraction occurs when a muscle changes length while the tension remains constant?

Accepted Answer

Isotonic contraction

Question 10

A muscle's ability to generate maximum force is greatest when its length is:

Accepted Answer

At an optimal resting length, allowing maximal overlap of actin and myosin.

Question 11

Which of the following statements about motor unit recruitment is correct?

Accepted Answer

Increasing the number of active motor units increases the force of muscle contraction.

Question 12

Which lever system is most common in the human body and is characterized by the effort being applied between the fulcrum and the load?

Accepted Answer

Third-class lever

Question 13

Which equation best represents aerobic respiration in muscle cells?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O + 36ATP}$$

Question 14

Which fascicle arrangement allows for the greatest range of motion but the least force production?

Accepted Answer

Parallel

Question 15

During shoulder abduction, which muscle acts as the prime mover?

Accepted Answer

Deltoid

Question 16

If the gastrocnemius muscle is injured, which movement would be most affected?

Accepted Answer

Plantar flexion of the foot

Question 17

Which muscle group is primarily responsible for knee extension?

Accepted Answer

Quadriceps femoris

Question 18

Which of the following best describes the action of the rotator cuff muscles?

Accepted Answer

They stabilize the shoulder joint during movement.

Question 19

Which muscle is primarily responsible for inhalation by increasing the volume of the thoracic cavity?

Accepted Answer

Diaphragm

Question 20

A patient suffers an injury to the biceps brachii. Which movement is most likely to be impaired?

Accepted Answer

Flexion of the forearm at the elbow

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