Question 1

Which structure surrounds an individual muscle fiber (cell)?

Accepted Answer

Endomysium

Question 2

During muscle contraction, which event directly triggers the release of Ca$^{2+}$ from the sarcoplasmic reticulum?

Accepted Answer

Action potential traveling down the T-tubule

Question 3

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

Accepted Answer

Tropomyosin

Question 4

What is the primary source of ATP for short, high-intensity muscle contractions?

Accepted Answer

Phosphorylation of ADP by creatine phosphate

Question 5

Which of the following best describes the I band in a sarcomere during muscle contraction?

Accepted Answer

It becomes shorter

Question 6

A patient is unable to relax their muscle after contraction. Which structure is most likely malfunctioning?

Accepted Answer

Sarcoplasmic reticulum

Question 7

Which of the following muscle fiber types has the highest endurance?

Accepted Answer

Slow oxidative

Question 8

What is the role of the Golgi tendon organ in muscle physiology?

Accepted Answer

Senses tension and causes muscle relaxation to prevent damage

Question 9

Which event marks the beginning of the cross-bridge cycle?

Accepted Answer

Myosin head binding to actin

Question 10

If a muscle fiber is stimulated at a high frequency, what is the expected effect on contraction?

Accepted Answer

Contraction strength increases and duration is prolonged

Question 11

Which equation correctly represents the reaction catalyzed by creatine kinase during muscle metabolism?

Accepted Answer

$\mathrm{ADP} + \mathrm{Creatine~Phosphate} \rightarrow \mathrm{ATP} + \mathrm{Creatine}$

Question 12

Which of the following is TRUE about multi-unit smooth muscle?

Accepted Answer

Each muscle fiber responds individually to autonomic neurons

Question 13

A muscle spindle is responsible for which of the following?

Accepted Answer

Detecting changes in muscle length and initiating contraction

Question 14

Which of the following best explains why fast glycolytic fibers fatigue quickly?

Accepted Answer

They rely primarily on anaerobic glycolysis for ATP production

Question 15

During excitation-contraction coupling, what is the role of the DHP receptor?

Accepted Answer

It senses the action potential in the T-tubule and triggers Ca$^{2+}$ release

Question 16

Which of the following is a correct sequence of events in the cross-bridge cycle?

Accepted Answer

Myosin binds to actin, power stroke occurs, ATP binds to myosin, myosin releases actin

Question 17

Which statement about the recruitment order of muscle fibers is correct?

Accepted Answer

Slow oxidative fibers are recruited first

Question 18

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

Accepted Answer

Binds Ca$^{2+}$ to move tropomyosin and expose myosin binding sites on actin

Question 19

A person is performing a sustained isometric contraction. Which metabolic pathway is most important for maintaining ATP supply?

Accepted Answer

Oxidative phosphorylation in mitochondria

Question 20

Which of the following is TRUE regarding the velocity of contraction in different muscle fiber types?

Accepted Answer

Slow oxidative fibers have slow contraction velocity

Muscle Structure, Function, and Physiology: Study Notes for Anatomy & Physiology

Study Guide - Practice Questions