Question 1

Which of the following best describes the phenomenon of tetanus in skeletal muscle physiology?

Accepted Answer

A sustained muscle contraction resulting from rapid, repeated stimulation without relaxation.

Question 2

A weightlifter is able to increase the strength of his muscle contractions over time. Which of the following cellular pathways is most directly responsible for this adaptation?

Accepted Answer

Increased recruitment of motor units and enhanced protein synthesis in muscle fibers.

Question 3

Which of the following is an example of an involuntary muscle contraction?

Accepted Answer

The rhythmic contractions of the heart.

Question 4

A patient is unable to voluntarily move their biceps muscle, but the muscle still contracts in response to electrical stimulation. What does this indicate about the muscle type and control?

Accepted Answer

The biceps is a skeletal muscle under voluntary control, but the neural pathway is disrupted.

Question 5

Which of the following best defines a motor unit?

Accepted Answer

A group of muscle fibers innervated by a single motor neuron.

Question 6

During a muscle twitch, which phase corresponds to the time when calcium ions are actively pumped back into the sarcoplasmic reticulum?

Accepted Answer

Relaxation phase

Question 7

If a muscle is repeatedly stimulated at a frequency that does not allow complete relaxation between stimuli, what is the physiological result?

Accepted Answer

Wave summation leading to increased tension.

Question 8

Which of the following equations best represents the relationship between force generated by a muscle and the number of active motor units?

Accepted Answer

$$F = k 	imes n$$

Question 9

A marathon runner experiences muscle fatigue during the last miles of a race. Which of the following is the most likely physiological cause?

Accepted Answer

Accumulation of lactic acid and depletion of ATP in muscle fibers.

Question 10

Which of the following scenarios best illustrates the concept of voluntary muscle contraction?

Accepted Answer

The contraction of skeletal muscles when lifting a glass of water.

Question 11

A muscle twitch is defined as:

Accepted Answer

A single, brief contraction and relaxation cycle in a muscle fiber.

Question 12

Which of the following best explains why increasing the frequency of action potentials in a motor neuron can lead to tetanus?

Accepted Answer

It causes calcium ions to accumulate in the cytosol, preventing relaxation.

Question 13

Which of the following is NOT a characteristic of skeletal muscle?

Accepted Answer

It contracts without neural stimulation.

Question 14

A person is able to increase the force of muscle contraction by:

Accepted Answer

Increasing the frequency of action potentials to the muscle.

Question 15

Which of the following best describes the process of summation in muscle physiology?

Accepted Answer

The addition of individual muscle twitches to produce a stronger contraction.

Question 16

Which of the following would most likely result in muscle fatigue during high-intensity exercise?

Accepted Answer

Depletion of glycogen stores and accumulation of metabolic byproducts.

Question 17

A patient with a neuromuscular disease has difficulty recruiting enough motor units for strong muscle contractions. Which of the following is most likely impaired?

Accepted Answer

The communication between motor neurons and muscle fibers at the neuromuscular junction.

Question 18

Which of the following best explains why skeletal muscle contractions are usually smooth and controlled rather than jerky?

Accepted Answer

Motor units are activated asynchronously and at varying frequencies.

Question 19

Which of the following is the correct sequence of events during a voluntary skeletal muscle contraction?

Accepted Answer

Action potential in motor neuron → release of acetylcholine → depolarization of muscle fiber → calcium release → cross-bridge cycling

Question 20

Which of the following best describes the relationship between muscle twitches and tetanus?

Accepted Answer

Tetanus results from the summation of multiple muscle twitches without relaxation.

Muscle Contraction and Skeletal Muscle Physiology Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard