Question 1

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

Accepted Answer

It breaks down acetylcholine in the synaptic cleft, terminating the signal.

Question 2

During a sustained muscle contraction, which process is primarily responsible for the removal of calcium ions from the sarcoplasm, leading to muscle relaxation?

Accepted Answer

Active transport of calcium ions into the sarcoplasmic reticulum using ATP.

Question 3

A weightlifter performing a biceps curl slowly lowers the weight back down after lifting it. Which type of muscle contraction is primarily occurring in the biceps during this phase?

Accepted Answer

Eccentric isotonic contraction

Question 4

Which of the following best explains why eccentric contractions are more likely to cause delayed-onset muscle soreness (DOMS) than concentric contractions?

Accepted Answer

Eccentric contractions generate greater force with fewer fibers, causing more microdamage.

Question 5

Which of the following is the correct sequence of events at the neuromuscular junction leading to muscle contraction?

Accepted Answer

Acetylcholine release → binding to receptors → sodium influx → action potential → calcium release

Question 6

A marathon runner relies primarily on which metabolic pathway for ATP production during the majority of the race?

Accepted Answer

Aerobic respiration (citric acid cycle and electron transport chain)

Question 7

Which of the following best describes the 'size principle' of motor unit recruitment?

Accepted Answer

Small motor units with the most excitable neurons are recruited first, followed by larger units as stimulus intensity increases.

Question 8

Which of the following is true regarding the length-tension relationship in skeletal muscle?

Accepted Answer

Maximum tension is generated when the muscle is slightly stretched, near its resting length.

Question 9

Which of the following best explains why muscle fatigue occurs during prolonged, intense exercise?

Accepted Answer

Accumulation of inorganic phosphate and ion imbalances reduce the ability to generate action potentials and cross-bridge cycling.

Question 10

Which of the following statements about smooth muscle contraction is correct?

Accepted Answer

Smooth muscle contraction is primarily triggered by calcium binding to calmodulin, not troponin.

Question 11

A patient is unable to relax their muscles after contraction, leading to continuous muscle tension. Which of the following is the most likely cause?

Accepted Answer

Impaired reuptake of calcium ions into the sarcoplasmic reticulum.

Question 12

Which of the following best describes the difference between isotonic and isometric muscle contractions?

Accepted Answer

Isotonic contractions involve muscle length change and movement of a load; isometric contractions generate tension without changing muscle length.

Question 13

Which of the following muscle fiber types is best suited for endurance activities such as long-distance running?

Accepted Answer

Slow oxidative fibers

Question 14

Which of the following is a characteristic of multiunit smooth muscle?

Accepted Answer

It is richly supplied with nerve endings and each fiber contracts independently.

Question 15

During the initial seconds of a 100-meter sprint, which energy source is primarily used by skeletal muscle?

Accepted Answer

Direct phosphorylation of ADP by creatine phosphate

Question 16

Which of the following best explains the phenomenon of 'wave summation' in muscle physiology?

Accepted Answer

Increasing the frequency of stimulation so that a second contraction occurs before the muscle has completely relaxed.

Question 17

Which of the following is a function of the 'excess post-exercise oxygen consumption' (EPOC) period?

Accepted Answer

To replenish oxygen reserves, restore ATP and creatine phosphate stores, and convert lactic acid to pyruvate or glucose.

Question 18

Which of the following best describes the mechanism by which smooth muscle can maintain contraction for long periods with minimal energy expenditure?

Accepted Answer

Smooth muscle has a 'latch state' where cross-bridges remain attached for extended periods, reducing ATP consumption.

Question 19

Which of the following is a unique feature of smooth muscle compared to skeletal muscle?

Accepted Answer

Smooth muscle uses calmodulin instead of troponin to bind calcium.

Muscle Contraction and Physiology: Study Notes for Anatomy & Physiology

Guida di studio - Domande di pratica

Study guide - Flashcard