Question 1

Which of the following best describes the relationship between sarcomere length and the force generated during skeletal muscle contraction?

Accepted Answer

Force generation is highest at an optimal sarcomere length (around $2.0$–$2.3\,\mu m$), where actin and myosin overlap is ideal.

Question 2

A patient is unable to generate maximal muscle force after prolonged, intense exercise. Which physiological phenomenon best explains this?

Accepted Answer

Muscle fatigue

Question 3

During an isometric contraction, which of the following occurs at the level of the sarcomere and the whole muscle?

Accepted Answer

Sarcomeres shorten, but the overall muscle length remains unchanged due to elastic elements stretching.

Question 4

Which process is directly responsible for the release of tension in a muscle after contraction?

Accepted Answer

Relaxation

Question 5

What is the primary effect of myostatin on skeletal muscle?

Accepted Answer

It inhibits muscle cell growth and differentiation.

Question 6

Which of the following best describes the sequence of events leading to a single muscle contraction?

Accepted Answer

Action potential at the neuromuscular junction → Excitation-contraction coupling → Contraction-relaxation cycle

Question 7

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

Accepted Answer

Unfused tetanus

Question 8

Which type of contraction occurs when a muscle creates force and shortens, such as when lifting a weight?

Accepted Answer

Concentric isotonic contraction

Question 9

If a muscle is held in complete tetanus for too long, what is the most likely outcome?

Accepted Answer

The muscle will fatigue and require a period of rest before it can contract again.

Question 10

Which of the following best explains why muscle hypertrophy occurs after resistance training?

Accepted Answer

Increase in the size and number of myofibrils within existing muscle fibers

Question 11

A muscle is stretched beyond its optimal resting length before contraction. What happens to the force it can generate?

Accepted Answer

Force decreases because actin and myosin overlap is reduced.

Question 12

Which of the following is a correct statement about muscle fatigue?

Accepted Answer

Fatigue can result from multiple factors, including ion imbalance, metabolic byproducts, and prolonged stimulation.

Question 13

During eccentric isotonic contraction, what happens to the muscle and the load?

Accepted Answer

The muscle lengthens while resisting the load.

Question 14

Which equation best represents the relationship between muscle tension ($T$), load ($L$), and movement in an isotonic contraction?

Accepted Answer

$T > L$; muscle shortens and moves the load

Question 15

Which of the following is true regarding the latent period in a muscle twitch?

Accepted Answer

It is the brief delay between the arrival of the action potential and the onset of contraction.

Question 16

A muscle that is not used for an extended period undergoes which process?

Accepted Answer

Atrophy

Question 17

Which of the following best describes the effect of summation on muscle tension?

Accepted Answer

Summation increases muscle tension by combining multiple twitches before full relaxation occurs.

Question 18

Which of the following is NOT a step in the process leading up to muscle contraction?

Accepted Answer

Muscle hypertrophy

Question 19

Which statement about the series elastic elements in muscle is correct?

Accepted Answer

They stretch during isometric contraction, allowing sarcomeres to shorten without changing overall muscle length.

Skeletal Muscle Contraction: Structure, Function, and Physiology

Study Guide - Practice Questions