Question 1

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

Accepted Answer

Conductivity: ability to transmit electrical impulses

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; instability of the sarcolemma leading to muscle fiber damage

Question 3

Which muscle tissue type is striated and involuntary?

Accepted Answer

Cardiac muscle

Question 4

During the sliding filament model of muscle contraction, which event occurs?

Accepted Answer

Thin filaments slide past thick filaments, increasing their overlap

Question 5

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

Accepted Answer

$$\mathrm{Creatine~phosphate} + \mathrm{ADP} \rightarrow \mathrm{Creatine} + \mathrm{ATP}$$

Question 6

A muscle contraction in which tension increases but the muscle does NOT shorten is called:

Accepted Answer

Isometric contraction

Question 7

Which of the following best explains why skeletal muscle fibers are multinucleated?

Accepted Answer

They are formed by the fusion of multiple myoblasts during development

Question 8

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

Accepted Answer

Sarcoplasmic reticulum

Question 9

A marathon runner’s muscles are likely to have increased numbers of which organelle due to endurance training?

Accepted Answer

Mitochondria

Question 10

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

Accepted Answer

It binds to chemically gated ion channels on the muscle fiber, causing depolarization

Question 11

Which factor does NOT increase the force of skeletal muscle contraction?

Accepted Answer

Stretching the muscle fibers beyond optimal length

Question 12

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

Accepted Answer

Smooth muscle

Question 13

Which of the following is TRUE regarding smooth muscle contraction?

Accepted Answer

It is regulated by nerves, hormones, or local chemical changes

Question 14

What is the function of the Na$$^+/K$^+$$ pump during muscle fiber repolarization?

Accepted Answer

It pumps Na$$^+$$ out of the cell and K$$^+$$ back into the cell

Question 15

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

Accepted Answer

It binds calcium ions, causing tropomyosin to move and expose actin binding sites

Question 16

Which type of contraction occurs when the biceps muscle lengthens while generating force, such as when lowering a book?

Accepted Answer

Eccentric contraction

Question 17

Which of the following is a direct attachment of skeletal muscle to bone?

Accepted Answer

The muscle is attached directly to the periosteum of the bone

Question 18

Which of the following is a result of resistance exercise (such as weight lifting) on skeletal muscle?

Accepted Answer

Hypertrophy, or increase in fiber size

Question 19

Which statement about gap junctions in smooth muscle is correct?

Accepted Answer

They allow molecules and ions to pass directly between adjacent cells

Question 20

A muscle fiber is stimulated by a motor neuron, leading to an action potential. Which equation best represents the change in membrane potential during depolarization?

Accepted Answer

$$\Delta V_{m} \u003e 0$$

Muscular System: Structure, Function, and Physiology

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