Q: Which equation correctly represents the net ATP yield from aerobic cellular respiration of one glucose molecule in muscle cells?

$$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O + 52 \text{ATP}$$

Question 1

Which of the following statements best describes the structural differences between skeletal, cardiac, and smooth muscle cells?

Accepted Answer

Skeletal muscle cells are long, cylindrical, and multinucleate with striations; cardiac muscle cells are branching, uninucleate, striated, and joined by intercalated discs; smooth muscle cells are spindle-shaped, uninucleate, and lack striations.

Question 2

Which connective tissue layer surrounds individual muscle fibers in skeletal muscle?

Accepted Answer

Endomysium

Question 3

A patient is experiencing muscle fatigue after prolonged exercise. Which of the following is LEAST likely to contribute to muscle fatigue?

Accepted Answer

Increase in oxygen supply

Question 4

Which of the following best explains why cardiac muscle cells contract at a steady rate?

Accepted Answer

They contain intercalated discs that allow rapid transmission of impulses and are regulated by a pacemaker.

Question 5

During muscle contraction, which event directly exposes the myosin-binding sites on actin filaments?

Accepted Answer

Binding of calcium ions to regulatory proteins on actin

Question 6

Which equation correctly represents the net ATP yield from aerobic cellular respiration of one glucose molecule in muscle cells?

Accepted Answer

$$C_6H_{12}O_6$ + 6O_2 ightarrow 6CO_2 + 6H_2O + 52 	ext{ATP}$$

Question 7

Which of the following is TRUE regarding the role of the sarcoplasmic reticulum (SR) in skeletal muscle contraction?

Accepted Answer

The SR stores and releases calcium ions, which are essential for contraction.

Question 8

A person is performing a plank exercise, holding their body in a fixed position. Which type of muscle contraction is primarily occurring?

Accepted Answer

Isometric contraction

Question 9

Which neurotransmitter is released at the neuromuscular junction to stimulate skeletal muscle contraction?

Accepted Answer

Acetylcholine (ACh)

Question 10

Which of the following best describes the difference in control between skeletal, cardiac, and smooth muscle?

Accepted Answer

Skeletal muscle is voluntary, cardiac muscle is involuntary, and smooth muscle is involuntary.

Question 11

Which structure is the contractile unit of a skeletal muscle fiber?

Accepted Answer

Sarcomere

Question 12

A marathon runner is able to sustain muscle activity for hours. Which energy pathway is primarily responsible for this endurance?

Accepted Answer

Aerobic cellular respiration

Question 13

Which of the following is a result of aerobic (endurance) exercise on muscle tissue?

Accepted Answer

Muscles become more resistant to fatigue and metabolism becomes more efficient.

Question 14

Which of the following best describes the role of tendons in the muscular system?

Accepted Answer

Tendons are cordlike structures made mostly of collagen that attach muscles to bones and often cross joints.

Question 15

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

Accepted Answer

Elasticity

Question 16

A patient with a neuromuscular disorder has impaired transmission at the neuromuscular junction. Which process is most directly affected?

Accepted Answer

Release of acetylcholine from the motor neuron

Question 17

Which of the following is TRUE about muscle tone?

Accepted Answer

It is a state of continuous partial contraction that keeps muscles firm and ready for action.

Question 18

Which of the following best explains why smooth muscle contractions are slow and sustained compared to skeletal muscle?

Accepted Answer

Smooth muscle cells lack striations and have different regulatory proteins.

Question 19

Which of the following scenarios best illustrates an isotonic muscle contraction?

Accepted Answer

Bending your knee while walking

Question 20

A muscle fiber is stimulated by a motor neuron. Which structure is the association site between the axon terminal and the muscle fiber?

Accepted Answer

Neuromuscular junction

Study Notes: The Muscular System (Anatomy & Physiology)

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