Q: Which equation best represents the ATP hydrolysis reaction that powers muscle contraction?

$$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + \mathrm{P}_i + \text{energy}$$

Question 1

Which of the following best describes the hierarchical organization of skeletal muscle from largest to smallest structure?

Accepted Answer

Muscle → Fascicle → Muscle fiber → Myofibril

Question 2

Which connective tissue layer surrounds individual muscle fibers?

Accepted Answer

Endomysium

Question 3

A patient presents with muscle weakness. Upon examination, you find damage to the sarcolemma. Which function is most likely to be impaired?

Accepted Answer

Transmission of action potentials into the muscle fiber

Question 4

Which of the following correctly matches the muscle structure with its description?

Accepted Answer

Muscle fiber: Single muscle cell

Question 5

During muscle contraction, which event occurs first?

Accepted Answer

Binding of acetylcholine to receptors on the sarcolemma

Question 6

Which equation best represents the ATP hydrolysis reaction that powers muscle contraction?

Accepted Answer

$$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} ightarrow \mathrm{ADP} + \mathrm{P}_i + 	ext{energy}$$

Question 7

A muscle fiber is unable to contract even though acetylcholine is present at the neuromuscular junction. Which structure is most likely malfunctioning?

Accepted Answer

Sarcoplasmic reticulum

Question 8

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

Accepted Answer

Acetylcholine binding → Action potential → Calcium release → Cross-bridge formation

Question 9

Which protein blocks the myosin binding sites on actin in a relaxed muscle?

Accepted Answer

Tropomyosin

Question 10

A marathon runner relies primarily on which type of muscle fibers for endurance activities?

Accepted Answer

Slow oxidative fibers

Question 11

Which of the following best explains why muscle cells contain multiple nuclei?

Accepted Answer

Because muscle fibers are formed by the fusion of multiple myoblasts

Question 12

If the perimysium is damaged, which structure is most directly affected?

Accepted Answer

Fascicle

Question 13

Which of the following is true regarding the sliding filament theory?

Accepted Answer

Sarcomeres shorten as actin and myosin filaments slide past each other

Question 14

A patient with myasthenia gravis has antibodies against acetylcholine receptors. Which process is most directly impaired?

Accepted Answer

Initiation of action potential in the muscle fiber

Question 15

Which equation represents the relationship between force, cross-sectional area, and muscle tension?

Accepted Answer

$$F = \sigma 	imes A$$

Question 16

Which structure stores calcium ions necessary for muscle contraction?

Accepted Answer

Sarcoplasmic reticulum

Question 17

Which of the following is a function of the T-tubules in skeletal muscle?

Accepted Answer

Transmit action potentials deep into the muscle fiber

Question 18

A muscle fiber is exposed to a toxin that prevents ATP synthesis. Which step of muscle contraction will be directly affected first?

Accepted Answer

Detachment of myosin heads from actin

Question 19

Which of the following best describes the role of troponin in muscle contraction?

Accepted Answer

Binds calcium ions and moves tropomyosin away from actin binding sites

Question 20

A sprinter relies on which metabolic pathway for rapid ATP production during a short burst of activity?

Accepted Answer

Creatine phosphate pathway

Muscular System: Structure and Function Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard