Q: Which equation best represents the action of the sodium-potassium pump in maintaining resting membrane potential?

$$3\ \text{Na}^+\ \text{out} + 2\ \text{K}^+\ \text{in}$$

Question 1

Which connective tissue sheath directly surrounds individual muscle fibers?

Accepted Answer

Endomysium

Question 2

A patient is diagnosed with Myasthenia Gravis, which impairs muscle contraction. Which component at the neuromuscular junction is most directly affected?

Accepted Answer

Acetylcholine receptors on the sarcolemma

Question 3

During muscle contraction, which event occurs first in the excitation-contraction coupling process?

Accepted Answer

Generation of an action potential at the sarcolemma

Question 4

Which muscle fiber type is most resistant to fatigue and is primarily used during endurance activities?

Accepted Answer

Slow oxidative fibers

Question 5

A muscle is described as bipennate. What does this indicate about its fascicle arrangement?

Accepted Answer

Fascicles insert into the tendon from two sides

Question 6

Which equation best represents the action of the sodium-potassium pump in maintaining resting membrane potential?

Accepted Answer

$$3\ 	ext{Na}^+\ 	ext{out} + 2\ 	ext{K}^+\ 	ext{in}$$

Question 7

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

Accepted Answer

Hormone secretion

Question 8

A muscle contraction in which the muscle length does not change, but tension increases, is called:

Accepted Answer

Isometric contraction

Question 9

Which structure is responsible for transmitting the action potential deep into the muscle fiber?

Accepted Answer

T-tubules

Question 10

Which of the following best explains why cardiac muscle is not prone to fatigue?

Accepted Answer

It contains a high percentage of mitochondria and relies almost exclusively on aerobic metabolism.

Question 11

Which of the following toxins blocks acetylcholine release at the neuromuscular junction, causing flaccid paralysis?

Accepted Answer

Botulinum toxin (botox)

Question 12

During the sliding filament model of muscle contraction, which molecule binds to troponin to initiate contraction?

Accepted Answer

Ca$$^{2+}$$

Question 13

Which phase of a muscle twitch corresponds to the time when Ca$$^{2+} is $$released and cross-bridge cycling occurs?

Accepted Answer

Period of contraction

Question 14

Which muscle attachment is typically more movable and is pulled toward the origin during contraction?

Accepted Answer

Insertion

Question 15

Which of the following best describes the metabolic characteristics of smooth muscle?

Accepted Answer

Low ATP requirement, few mitochondria, primarily aerobic

Question 16

A muscle fiber is stretched beyond its optimal length before contraction. What is the likely effect on force production?

Accepted Answer

Force production decreases due to fewer cross-bridges

Question 17

Which of the following is TRUE regarding smooth muscle contraction?

Accepted Answer

Ca$$^{2+}$$ binds to calmodulin to initiate contraction

Question 18

Which muscle shape is most efficient for generating force due to its arrangement of short, densely packed fascicles?

Accepted Answer

Multipennate

Question 19

Which of the following best describes the process of rigor mortis?

Accepted Answer

Muscles stiffen because ATP is unavailable for detachment of myosin from actin

Question 20

Which of the following is a real-life example of a muscle acting as a fixator?

Accepted Answer

The rotator cuff muscles stabilizing the shoulder during arm movement

Muscular System: Structure, Function, and Physiology (Chapters 9 & 10.1-10.3)

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