Question 1

Which property of muscle tissue allows a muscle to return to its original resting length after being stretched?

Accepted Answer

Elasticity

Question 2

A patient is unable to maintain posture due to a muscular disorder. Which function of the muscular system is most directly affected?

Accepted Answer

Maintenance of posture

Question 3

Which connective tissue layer surrounds individual muscle fibers?

Accepted Answer

Endomysium

Question 4

During muscle contraction, which event occurs first after an action potential reaches the neuromuscular junction?

Accepted Answer

Release of acetylcholine (ACh) from synaptic vesicles

Question 5

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

Accepted Answer

It binds Ca$$^{2+}$$, causing a conformational change that exposes actin's binding sites

Question 6

If the resting membrane potential of a skeletal muscle cell is $$-80\ \mathrm{mV}$$, what would happen if voltage-gated Na$$^+$$ channels suddenly opened?

Accepted Answer

The membrane would depolarize

Question 7

Which equation correctly represents the immediate energy source for muscle contraction involving creatine phosphate?

Accepted Answer

$$\mathrm{ADP} + \mathrm{CP} \rightarrow \mathrm{Creatine} + \mathrm{ATP}$$

Question 8

Which type of muscle fiber is most likely to be found in the lower limb muscles of a marathon runner?

Accepted Answer

Slow-twitch fibers

Question 9

A muscle is stretched so that its sarcomeres are longer than optimal. What is the expected effect on tension generation?

Accepted Answer

Tension decreases because fewer cross-bridges can form

Question 10

Which of the following is TRUE regarding smooth muscle contraction?

Accepted Answer

It can be initiated by Ca$$^{2+}$$ binding to calmodulin

Question 11

Which statement best explains why rigor mortis occurs after death?

Accepted Answer

ATP is depleted, preventing myosin heads from releasing actin

Question 12

Which phase of the action potential is characterized by the opening of voltage-gated K$$^+$$ channels?

Accepted Answer

Repolarization

Question 13

Which muscle type contains intercalated disks and is autorhythmic?

Accepted Answer

Cardiac muscle

Question 14

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

Accepted Answer

Isometric contraction

Question 15

Which of the following is a function of the sarcoplasmic reticulum in skeletal muscle cells?

Accepted Answer

Storing and releasing Ca$$^{2+}$$ for contraction

Question 16

Which of the following best describes the 'all-or-none' principle in muscle fibers?

Accepted Answer

A muscle fiber contracts maximally if threshold is reached, or not at all

Question 17

Which process is responsible for the graded strength of muscle contraction?

Accepted Answer

Recruitment of motor units

Question 18

Which of the following is TRUE about fast-twitch muscle fibers?

Accepted Answer

They fatigue quickly and are specialized for rapid, powerful bursts

Question 19

Which of the following is a correct statement about the role of acetylcholinesterase at the neuromuscular junction?

Accepted Answer

It breaks down acetylcholine, preventing continuous stimulation of the muscle

Question 20

Which type of smooth muscle is most likely to be found in the walls of the digestive tract, producing waves of contraction?

Accepted Answer

Visceral (unitary) smooth muscle

Muscular System: Histology and Physiology – Study Notes

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