Question 1

Which of the following best describes a motor unit in skeletal muscle?

Accepted Answer

A motor neuron and all of the muscle fibers it innervates

Question 2

During a muscle twitch, which phase corresponds to the time when cross-bridges are actively cycling and muscle tension increases?

Accepted Answer

Contraction period

Question 3

A patient is unable to maintain a sustained muscle contraction and experiences rapid fatigue. Which metabolic pathway is most likely being relied upon for ATP production?

Accepted Answer

Anaerobic glycolysis (glycogen-lactic acid system)

Question 4

Which of the following best explains why wave summation leads to a stronger muscle contraction?

Accepted Answer

Calcium ions are not fully cleared from the cytosol between stimuli

Question 5

Which type of muscle contraction occurs when a muscle generates force while shortening?

Accepted Answer

Concentric isotonic contraction

Question 6

A weightlifter holds a heavy barbell stationary above their head without moving it. What type of muscle contraction is primarily occurring in their muscles?

Accepted Answer

Isometric contraction

Question 7

Which of the following is NOT a factor that increases the force of skeletal muscle contraction?

Accepted Answer

Decreasing the size of muscle fibers

Question 8

A marathon runner is able to sustain muscle activity for hours. Which muscle fiber type is most abundant in their leg muscles?

Accepted Answer

Slow oxidative fibers

Question 9

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

Accepted Answer

Small motor units are recruited first, followed by larger ones as stimulus strength increases

Question 10

Which of the following statements about muscle fatigue is correct?

Accepted Answer

It can result from ionic disturbances, such as excess $$K^+ in $$the extracellular fluid

Question 11

After intense exercise, a person continues to breathe heavily. This is primarily due to:

Accepted Answer

The need to replenish oxygen debt and restore metabolic conditions

Question 12

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

Accepted Answer

Contraction is regulated by calmodulin and myosin light chain kinase (MLCK)

Question 13

Which of the following best explains why muscle tone is important for the body?

Accepted Answer

It keeps muscles ready for action, maintains posture, and stabilizes joints

Question 14

A patient with a spinal cord injury loses voluntary control of skeletal muscles but still has some muscle tone. What is the most likely explanation?

Accepted Answer

Muscle tone is maintained by spinal reflexes independent of voluntary control

Question 15

Which of the following best describes the relationship between sarcomere length and force of contraction?

Accepted Answer

Force is greatest at an optimal sarcomere length, typically 80-120% of resting length

Question 16

Which of the following is a characteristic of single-unit (visceral) smooth muscle?

Accepted Answer

Cells are electrically coupled by gap junctions and contract as a unit

Question 17

Which of the following best explains why resistance exercise leads to muscle hypertrophy?

Accepted Answer

It increases the size of individual muscle fibers

Question 18

Which of the following is a correct sequence of events in excitation-contraction coupling in smooth muscle?

Accepted Answer

Calcium binds to calmodulin → activates MLCK → myosin is phosphorylated

Question 19

A sprinter uses which energy system predominantly during the first 10 seconds of a 100-meter dash?

Accepted Answer

Phosphagen system (creatine phosphate)

Question 20

Which of the following is a likely consequence of disuse atrophy?

Accepted Answer

Decrease in muscle mass and strength

Muscle Contraction, Metabolism, and Fiber Types: Study Notes for Anatomy & Physiology

Guida di studio - Domande di pratica

Study guide - Flashcard