Question 1

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

Accepted Answer

Endomysium

Question 2

During muscle contraction, which structure releases Ca$$^{2+}$$ ions to trigger the interaction of thick and thin filaments?

Accepted Answer

Sarcoplasmic reticulum

Question 3

What is the primary function of the perimysium in skeletal muscle?

Accepted Answer

Surrounds bundles of muscle fibers (fascicles) and contains blood vessels and nerves

Question 4

Which protein prevents actin–myosin interaction in a resting muscle?

Accepted Answer

Tropomyosin

Question 5

A patient with muscle cramps is found to have a deficiency in ATP. Which process is most directly affected?

Accepted Answer

Pumping Ca$$^{2+}$$ back into the sarcoplasmic reticulum

Question 6

Which of the following best describes the sliding filament theory?

Accepted Answer

Thin filaments slide toward the M line alongside thick filaments, causing Z lines to move closer together

Question 7

Which event occurs first in the contraction cycle of skeletal muscle?

Accepted Answer

Exposure of active sites

Question 8

What is the role of acetylcholinesterase (AChE) at the neuromuscular junction?

Accepted Answer

It breaks down acetylcholine, preventing continued muscle contraction

Question 9

Which of the following is TRUE regarding the sarcomere during muscle contraction?

Accepted Answer

The Z lines move closer together

Question 10

A muscle biopsy reveals an abundance of myosatellite cells. What is the most likely function of these cells?

Accepted Answer

Repair muscle damage

Question 11

Which equation best represents the relationship between muscle tension and ATP availability?

Accepted Answer

$$T \propto [ATP]$$

Question 12

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

Accepted Answer

T-tubules

Question 13

In a patient with rigor mortis, which of the following best explains the inability of muscles to relax after death?

Accepted Answer

Ion pumps cease to function, Ca$$^{2+}$$ builds up, and ATP is unavailable for relaxation

Question 14

Which protein stabilizes thick filaments by connecting them to the Z line in the sarcomere?

Accepted Answer

Titin

Question 15

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

Accepted Answer

Pump blood throughout the body

Question 16

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

Accepted Answer

Binds to G-actin and tropomyosin, controlled by Ca$$^{2+}$$

Question 17

Which of the following is the correct sequence for the contraction cycle?

Accepted Answer

Exposure of active sites, formation of cross-bridges, pivoting of myosin heads, detachment, reactivation

Question 18

Which of the following would most likely result in a muscle that is partially contracted and unable to relax?

Accepted Answer

Lack of ATP to pump Ca$$^{2+}$$ back into the sarcoplasmic reticulum

Question 19

Which of the following is TRUE regarding the neuromuscular junction?

Accepted Answer

Acetylcholine binds to receptors on the sarcolemma, causing Na$$^+$$ influx

Question 20

Which of the following best describes the relationship between the sarcolemma and the T-tubules?

Accepted Answer

T-tubules are extensions of the sarcolemma that transmit action potentials into the muscle fiber

Skeletal Muscle Tissue: Structure and Function

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