Question 1

Which phase of a muscle twitch is characterized by the re-entry of $$Ca^{2+}$$ into the sarcoplasmic reticulum, resulting in a gradual reduction of tension to zero?

Accepted Answer

Period of relaxation

Question 2

A motor unit consists of:

Accepted Answer

A motor neuron and all the muscle fibers it supplies

Question 3

During a biceps curl, the muscle shortens as it lifts the weight. This type of contraction is best described as:

Accepted Answer

Concentric isotonic contraction

Question 4

Which of the following best explains why greater cytosolic $$Ca^{2+}$$ promotes stronger muscle contraction?

Accepted Answer

It enhances the cross-bridge cycling between actin and myosin

Question 5

Which pathway provides the fastest regeneration of ATP in muscle cells but is only sustainable for about 15 seconds?

Accepted Answer

Creatine phosphate pathway

Question 6

What is the chemical reaction for ATP regeneration using creatine phosphate?

Accepted Answer

$$CP + ADP \rightarrow Creatine + ATP$$

Question 7

Which muscle fiber type is most resistant to fatigue and is best suited for marathon running?

Accepted Answer

Slow oxidative fibers

Question 8

A weightlifter performing a slow, controlled lowering of a heavy barbell is primarily using which type of muscle contraction?

Accepted Answer

Eccentric contraction

Question 9

Which process is responsible for the majority of ATP production during prolonged, moderate-intensity exercise?

Accepted Answer

Aerobic respiration

Question 10

If a muscle cell is stimulated at a high frequency such that it does not relax between stimuli, what is the resulting contraction called?

Accepted Answer

Fused (complete) tetanus

Question 11

Which of the following is NOT a function for which muscle cells use ATP?

Accepted Answer

Synthesizing actin filaments

Question 12

Which muscle fiber type is characterized by rapid contraction, low endurance, and little myoglobin?

Accepted Answer

Fast glycolytic fibers

Question 13

During anaerobic glycolysis, what is the net ATP yield per glucose molecule?

Accepted Answer

$$2$$ ATP

Question 14

Which of the following best describes the Cori cycle?

Accepted Answer

Conversion of lactic acid to glucose in the liver

Question 15

Which of the following is true regarding motor units in muscles that control fine movements (e.g., fingers, eyes)?

Accepted Answer

Each motor neuron innervates few muscle fibers

Question 16

A patient is unable to maintain posture for long periods and experiences rapid muscle fatigue. Which muscle fiber type is most likely deficient?

Accepted Answer

Slow oxidative fibers

Question 17

Which of the following is a multi-step process that occurs during the cross-bridge cycle in muscle contraction?

Accepted Answer

ATP binds to myosin, causing it to detach from actin; ATP is hydrolyzed, re-cocking the myosin head

Question 18

Which of the following best explains why asynchronous contraction of motor units helps prevent muscle fatigue?

Accepted Answer

It allows some motor units to rest while others contract

Question 19

Which muscle fiber type is most likely to be predominant in a sprinter's leg muscles?

Accepted Answer

Fast glycolytic fibers

Question 20

Which equation best represents aerobic respiration in muscle cells?

Accepted Answer

$$Glucose + O_2$ \rightarrow CO_2$ + H_2O + ATP$$

Lecture #20

Guida di studio - Domande di pratica

Study guide - Flashcard