Question 1

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

Accepted Answer

Producing hormones

Question 2

A patient presents with muscle weakness and inability to maintain posture. Which property of muscle cells is most likely compromised?

Accepted Answer

Excitability

Question 3

Which connective tissue layer surrounds individual muscle fibers?

Accepted Answer

Endomysium

Question 4

During muscle contraction, which event directly follows the binding of ATP to the myosin head?

Accepted Answer

Detachment of myosin from actin

Question 5

Which protein is responsible for blocking the active sites on actin in a relaxed muscle?

Accepted Answer

Tropomyosin

Question 6

What is the primary ion responsible for depolarization during an action potential in skeletal muscle?

Accepted Answer

Na$$^+$$

Question 7

Which equation best represents the electrochemical gradient for potassium ions ($$K^+) $$across the sarcolemma?

Accepted Answer

$$E_{K^+} = \frac{RT}{zF} \ln \left( \frac{[K^+]_{out}}{[K^+]_{in}} \right)$$

Question 8

A toxin blocks acetylcholinesterase at the neuromuscular junction. What is the most likely effect?

Accepted Answer

Acetylcholine accumulates, causing prolonged muscle contraction

Question 9

Which of the following best describes the role of the sarcoplasmic reticulum during muscle contraction?

Accepted Answer

It releases Ca$$^{2+}$$ into the cytosol

Question 10

A patient with a genetic defect in titin protein would most likely have problems with which muscle property?

Accepted Answer

Elasticity

Question 11

Which of the following events occurs FIRST during excitation-contraction coupling?

Accepted Answer

Opening of voltage-gated Na$$^+$$ channels in the sarcolemma

Question 12

Which structure serves as the anchoring point for thin filaments in the sarcomere?

Accepted Answer

Z disc

Question 13

What is the effect of the hydrophobic phospholipid bilayer of the plasma membrane on ion movement?

Accepted Answer

It is impermeable to ions, requiring protein channels for ion movement

Question 14

Which of the following best explains why rigor mortis occurs after death?

Accepted Answer

ATP is no longer available to detach myosin heads from actin

Question 15

Which of the following is TRUE regarding the propagation of action potentials in skeletal muscle?

Accepted Answer

Action potentials are conducted throughout the entire sarcolemma, including T-tubules

Question 16

Which of the following is the correct sequence of events in the crossbridge cycle?

Accepted Answer

Myosin binds to actin, power stroke, ATP binds to myosin, myosin detaches

Question 17

Which of the following best describes the role of acetylcholine at the neuromuscular junction?

Accepted Answer

It opens ligand-gated Na$$^+$$ channels on the motor end plate

Question 18

A muscle cell is unable to return to its original length after stretching. Which property is most likely affected?

Accepted Answer

Elasticity

Question 19

Which of the following is TRUE regarding the resting membrane potential of a skeletal muscle cell?

Accepted Answer

The cytosol is approximately 90 mV more negative than the extracellular fluid

Question 20

Which of the following best describes the function of regulatory proteins in muscle fibers?

Accepted Answer

They dictate when a fiber may contract

Muscle Tissue and Physiology: Chapter 10 Study Notes

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