Question 1

Which of the following best describes the role of collagen fibers in muscle tissue mechanics?

Accepted Answer

They do not resist compression but have very high tensile resistance, effectively transferring muscle tension to objects.

Question 2

A patient receives an intramuscular injection in the vastus lateralis. Why is this muscle preferred for injections in children and the elderly?

Accepted Answer

It is well-developed and has fewer major nerves and vessels, reducing risk of injury and ensuring effective drug absorption.

Question 3

Which property of muscle tissue allows it to return to its original length after being stretched or contracted?

Accepted Answer

Elasticity

Question 4

During muscle contraction, which event occurs at the sarcomere level?

Accepted Answer

The thin filaments slide past the thick filaments, causing the H-zone to disappear and Z-discs to move closer together.

Question 5

Which of the following is TRUE regarding the nervous control of skeletal muscle fibers?

Accepted Answer

They are innervated by somatic nerve fibers and require an intrinsic signal from the nervous system to contract.

Question 6

Which connective tissue layer surrounds individual muscle fibers and contains capillary networks?

Accepted Answer

Endomysium

Question 7

A patient exposed to organophosphate nerve gas (e.g., Sarin) would most likely experience which physiological effect?

Accepted Answer

Paralysis of skeletal muscles, including the diaphragm, due to inhibition of acetylcholinesterase.

Question 8

Which of the following best explains why skeletal muscle is striated?

Accepted Answer

The precise organization and alignment of thick and thin myofilaments into repeating sarcomeres.

Question 9

Which event directly triggers the release of calcium ions from the sarcoplasmic reticulum during excitation-contraction coupling?

Accepted Answer

Depolarization of the T-tubule membrane, causing voltage-sensor proteins to open mechanically-gated Ca$$^{2+}$$ channels.

Question 10

Which protein anchors thick myofilaments at the M-line and helps maintain sarcomere structure?

Accepted Answer

Myomesin

Question 11

What is the primary function of the T-tubules in skeletal muscle fibers?

Accepted Answer

To relay action potentials deep into the muscle fiber, ensuring rapid and uniform contraction.

Question 12

Which of the following correctly matches the muscle type with its control mechanism?

Accepted Answer

Smooth muscle: involuntary control via autonomic nervous system

Question 13

During the cross-bridge cycle, which molecule binds to the myosin head to provide energy for contraction?

Accepted Answer

Adenosine triphosphate (ATP)

Question 14

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

Accepted Answer

It covers actin binding sites on the thin filament, preventing myosin interaction in the resting state.

Question 15

A competitive inhibitor of the nicotinic acetylcholine receptor (nAChR) would most likely cause which effect at the neuromuscular junction?

Accepted Answer

Temporary paralysis by preventing acetylcholine from binding to its receptor.

Question 16

Which equation best represents the relationship between muscle tension ($$T$$), resistance ($$R$$), and movement?

Accepted Answer

$$T \u003e R$$

Question 17

Which of the following is a function of skeletal muscle that contributes to homeostasis?

Accepted Answer

Thermoregulation through heat production during contraction.

Question 18

Which statement about the sarcolemma is correct?

Accepted Answer

It is the plasma membrane of the muscle fiber and is electrically excitable, allowing action potentials to propagate.

Question 19

Which of the following best explains the effect of acetylcholinesterase at the neuromuscular junction?

Accepted Answer

It hydrolyzes acetylcholine, terminating its effect and allowing muscle relaxation.

Question 20

Which of the following is TRUE regarding the arrangement of myofibrils in skeletal muscle fibers?

Accepted Answer

Myofibrils are precisely aligned, resulting in the striated appearance of skeletal muscle.

Muscle and Muscle Tissue: Structure, Function, and Control

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