Question 1

Which of the following best describes the role of creatine phosphate (CP) in muscle contraction during a 100-meter sprint?

Accepted Answer

CP acts as a storage molecule for excess ATP and rapidly regenerates ATP from ADP during short, intense activity.

Question 2

During peak short burst muscular activity, which metabolic pathway predominates in ATP production?

Accepted Answer

Anaerobic glycolysis in the cytoplasm.

Question 3

A muscle fiber is stimulated repeatedly before it has fully relaxed, resulting in increasing tension. What is this phenomenon called?

Accepted Answer

Summation

Question 4

Which equation correctly represents the reaction catalyzed by creatine phosphokinase (CPK) to recharge ATP in muscle cells?

Accepted Answer

$$\mathrm{ADP} + \mathrm{CP} \xrightarrow{CPK} \mathrm{ATP} + \mathrm{Creatine}$$

Question 5

Which of the following is a major cause of muscle fatigue during intense exercise?

Accepted Answer

Low pH due to lactic acid buildup.

Question 6

What is the primary energy source for skeletal muscles at rest?

Accepted Answer

Aerobic metabolism of fatty acids and glucose.

Question 7

Which type of muscle contraction occurs when muscle tension increases but the muscle length does not change?

Accepted Answer

Isometric contraction

Question 8

A patient is unable to maintain posture due to decreased muscle tone. Which of the following best explains muscle tone?

Accepted Answer

The normal tension and firmness of a muscle at rest.

Question 9

Which of the following factors does NOT directly affect the tension developed in a single muscle fiber during contraction?

Accepted Answer

The total number of motor units in the whole muscle.

Question 10

Which type of skeletal muscle fiber is most abundant in postural muscles and is characterized by high myoglobin content and many mitochondria?

Accepted Answer

Slow-twitch oxidative fibers

Question 11

A muscle is contracting and shortening as you lift a dumbbell. What type of contraction is this?

Accepted Answer

Concentric isotonic contraction

Question 12

Which of the following best explains why muscles experience 'oxygen debt' after intense exercise?

Accepted Answer

The body needs extra oxygen to convert lactic acid back to pyruvate and restore creatine phosphate stores.

Question 13

Which of the following is TRUE regarding cardiac muscle cells (cardiomyocytes)?

Accepted Answer

They are small, faintly striated, and connected by intercalated discs.

Question 14

Which of the following is a function of intercalated discs in cardiac muscle?

Accepted Answer

They enhance mechanical and electrical connections between cells.

Question 15

Which of the following best describes the difference between fast-twitch and slow-twitch muscle fibers?

Accepted Answer

Slow-twitch fibers are more resistant to fatigue and rely on aerobic metabolism.

Question 16

Which process is responsible for the rapid production of ATP in the absence of oxygen, and what is its byproduct?

Accepted Answer

Anaerobic glycolysis; lactic acid

Question 17

A muscle fiber is stretched beyond its optimal sarcomere length before stimulation. What is the expected effect on tension production?

Accepted Answer

Tension production will decrease due to reduced overlap between thick and thin filaments.

Question 18

Which of the following training regimens is most likely to increase the diameter of muscle fibers and the number of myofibrils?

Accepted Answer

Strength training with brief, intensive workouts

Question 19

Which of the following is TRUE about smooth muscle cells?

Accepted Answer

They are spindle-shaped, have a single central nucleus, and lack sarcomeres.

Question 20

Which of the following best explains the concept of 'recruitment' in whole muscle contraction?

Accepted Answer

Gradually increasing the number of motor units stimulated to produce greater muscle strength.

Muscle Tissue & Muscular System: Energy, Contraction, and Fiber Types

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