Question 1

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

Accepted Answer

Conducting electrical impulses for communication

Question 2

A patient is exposed to curare, a poison that acts as a competitive antagonist at acetylcholine (ACh) receptors. What is the most immediate effect on skeletal muscle contraction?

Accepted Answer

Muscle fibers will be unable to respond to neural stimulation, resulting in paralysis

Question 3

During the cross bridge cycle, which step requires ATP binding to the myosin head?

Accepted Answer

Detachment of myosin from actin

Question 4

Which layer of connective tissue surrounds individual muscle fibers and contains capillaries, nerve fibers, and myosatellite cells?

Accepted Answer

Endomysium

Question 5

A muscle fiber is stimulated repeatedly before it has fully relaxed, resulting in increased tension. This phenomenon is known as:

Accepted Answer

Wave summation

Question 6

Which of the following statements about the sarcomere is TRUE?

Accepted Answer

The H-zone is the region with no actin or myosin filaments

Question 7

What is the primary role of the sarcoplasmic reticulum (SR) in muscle contraction?

Accepted Answer

Storing and releasing calcium ions ($$\mathrm{Ca$$^{2+}$$})$$

Question 8

Which event directly triggers the release of acetylcholine (ACh) from the motor neuron at the neuromuscular junction?

Accepted Answer

Influx of $$\mathrm{Ca$$^{2+}$$}$$ into the axon terminal

Question 9

A patient exposed to sarin gas will experience which of the following at the neuromuscular junction?

Accepted Answer

Continuous muscle contraction due to inhibition of acetylcholinesterase

Question 10

Which of the following best describes the 'sliding filament theory' of muscle contraction?

Accepted Answer

Actin filaments slide toward the M-line, shortening the sarcomere

Question 11

Which protein complex regulates the exposure of active sites on actin for myosin binding?

Accepted Answer

Troponin-tropomyosin complex

Question 12

During muscle contraction, which band decreases in size as the sarcomere shortens?

Accepted Answer

I band

Question 13

Which of the following equations correctly represents the hydrolysis of ATP by the myosin head during the cross bridge cycle?

Accepted Answer

$$\mathrm{ATP} \rightarrow \mathrm{ADP} + \mathrm{Pi}$$

Question 14

Which scenario would most likely result in rigor mortis after death?

Accepted Answer

No ATP is available, preventing detachment of myosin from actin

Question 15

Which of the following best describes the function of T-tubules in skeletal muscle fibers?

Accepted Answer

Propagate depolarization deep into the muscle fiber

Question 16

A muscle is stimulated at a frequency high enough that it never relaxes and remains in continuous contraction. This state is called:

Accepted Answer

Complete tetanus

Question 17

Which of the following is TRUE regarding the muscular system?

Accepted Answer

It only includes skeletal muscles

Question 18

Which of the following is a real-life consequence of acetylcholinesterase inhibition, as seen with exposure to sarin gas?

Accepted Answer

Continuous muscle contraction leading to respiratory paralysis

Question 19

Which of the following best explains why cardiac muscle typically exhibits treppe but not skeletal muscle?

Accepted Answer

Cardiac muscle has a gradual increase in cytosolic $$\mathrm{Ca$$^{2+}$$}$$ with repeated stimulation

Question 20

Which of the following correctly describes the sequence of events at the neuromuscular junction leading to muscle contraction?

Accepted Answer

ACh binds to receptors, sodium enters the motor end plate, sarcolemma depolarizes, voltage-gated $$\mathrm{Ca$$^{2+}$$}$$ channels open, $$\mathrm{Ca$$^{2+}$$} is $$released from SR

Chapter 10: The Muscular System – Structure and Function of Muscle Tissue

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