$$\mathrm{ATP} \rightarrow \mathrm{ADP} + \mathrm{P_i} + \text{energy}$$

Question 1

Which of the following is NOT a primary characteristic of muscle tissue?

Accepted Answer

Rigidity: ability to resist deformation

Question 2

A patient with Duchenne muscular dystrophy (DMD) is most likely to have a defect in which protein, and what is the consequence?

Accepted Answer

Dystrophin; sarcolemma tears easily, leading to muscle degeneration

Question 3

Which muscle tissue type is striated and involuntary, and where is it found?

Accepted Answer

Cardiac muscle; walls of the heart

Question 4

During the sliding filament model of muscle contraction, what happens to the length of the thick and thin filaments?

Accepted Answer

Neither filament changes length; they slide past each other

Question 5

Which equation best represents the immediate source of energy for muscle contraction?

Accepted Answer

$$\mathrm{ATP} ightarrow \mathrm{ADP} + \mathrm{P_i} + 	ext{energy}$$

Question 6

Which of the following best describes an isometric contraction?

Accepted Answer

Muscle tension increases, but the muscle does not shorten

Question 7

A marathon runner’s muscles adapt to endurance exercise by increasing which of the following?

Accepted Answer

Number of mitochondria and capillaries

Question 8

Which structure in a skeletal muscle fiber stores calcium ions and releases them during contraction?

Accepted Answer

Sarcoplasmic reticulum

Question 9

What is the role of acetylcholinesterase at the neuromuscular junction?

Accepted Answer

It breaks down acetylcholine, terminating the signal

Question 10

Which of the following factors does NOT increase the force of skeletal muscle contraction?

Accepted Answer

Stretching the muscle fibers beyond optimal length

Question 11

A weightlifter performing resistance exercise will experience which adaptation in their skeletal muscles?

Accepted Answer

Increase in fiber size (hypertrophy)

Question 12

Which of the following best describes the arrangement of myofilaments in a sarcomere?

Accepted Answer

Thin filaments are composed of actin, thick filaments of myosin, arranged in a repeating pattern

Question 13

Which type of muscle tissue is found in the walls of hollow organs and is responsible for peristalsis?

Accepted Answer

Smooth muscle

Question 14

What is the effect of neurotransmitter binding on smooth muscle in different organs?

Accepted Answer

It can be stimulatory in one organ and inhibitory in another

Question 15

Which of the following is TRUE regarding the transmission of action potentials in smooth muscle?

Accepted Answer

Action potentials are transmitted via gap junctions between adjacent cells

Question 16

Which process is responsible for restoring the resting membrane potential after muscle fiber depolarization?

Accepted Answer

Efflux of K+ ions and activity of the Na+-K+ pump

Question 17

Which of the following best describes concentric contraction?

Accepted Answer

Muscle shortens and does work

Question 18

Which of the following is a function of skeletal muscle?

Accepted Answer

Maintaining posture and body position

Question 19

Which of the following is TRUE about the energy supply for muscle contraction?

Accepted Answer

ATP must be regenerated quickly because stores are depleted in 4-6 seconds

Question 20

Which of the following is a correct sequence of events at the neuromuscular junction leading to muscle contraction?

Accepted Answer

Release of acetylcholine, binding to receptors, opening of Na+ channels, depolarization

Muscular System: Structure, Function, and Physiology

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