Question 1

Which connective tissue layer directly surrounds each individual skeletal muscle fiber?

Accepted Answer

Endomysium

Question 2

During a biceps curl, which muscle acts as the agonist (prime mover) for elbow flexion?

Accepted Answer

Brachialis

Question 3

Which of the following best describes the function of the sarcoplasmic reticulum in skeletal muscle fibers?

Accepted Answer

It stores and releases calcium ions ($$\mathrm{Ca$$^{2+}$$}) $$during muscle contraction.

Question 4

Which of the following is a distinguishing feature of cardiac muscle tissue?

Accepted Answer

Intercalated discs

Question 5

A patient with Duchenne Muscular Dystrophy (DMD) lacks which critical protein, leading to muscle fiber degeneration?

Accepted Answer

Dystrophin

Question 6

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

Accepted Answer

ATP is no longer produced, so $$\mathrm{Ca$$^{2+}$$}$$ remains in the cytosol and myosin heads cannot detach from actin.

Question 7

Which type of muscle contraction occurs when the muscle length remains unchanged despite tension generation?

Accepted Answer

Isometric contraction

Question 8

Which energy system provides ATP for the first 10 seconds of intense muscle activity?

Accepted Answer

Immediate cytosolic reactions using creatine phosphate

Question 9

What is the primary function of the T-tubules in skeletal muscle fibers?

Accepted Answer

To conduct action potentials deep into the muscle fiber

Question 10

Which of the following best describes the sliding filament theory of muscle contraction?

Accepted Answer

The I band and H zone narrow, while the A band remains unchanged

Question 11

A muscle fiber is stimulated repeatedly at a frequency of 90 stimuli per second, resulting in no relaxation between contractions. What is this phenomenon called?

Accepted Answer

Fused (complete) tetanus

Question 12

Which type of skeletal muscle fiber is most resistant to fatigue and is predominant in postural muscles?

Accepted Answer

Type I (slow oxidative)

Question 13

Which of the following is a function of single-unit smooth muscle?

Accepted Answer

Coordinated contraction in the walls of hollow organs

Question 14

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

Accepted Answer

It degrades acetylcholine in the synaptic cleft, ending muscle stimulation.

Question 15

A patient is exposed to botulinum toxin. What is the most likely physiological effect on their skeletal muscles?

Accepted Answer

Paralysis due to blocked acetylcholine release

Question 16

Which of the following best explains why delayed-onset muscle soreness (DOMS) occurs after intense exercise?

Accepted Answer

Minor structural damage, especially from eccentric contractions

Question 17

Which of the following is NOT a property of muscle cells?

Accepted Answer

Ossification

Question 18

Which of the following best describes the function of a fixator muscle during movement?

Accepted Answer

It stabilizes a bone to prevent unnecessary movement.

Question 19

Which of the following is true regarding the origin and insertion of a skeletal muscle?

Accepted Answer

The origin is the anchoring point, and the insertion moves during contraction.

Question 20

Which of the following best describes the arrangement of thick and thin filaments in a sarcomere during contraction?

Accepted Answer

Thick filaments slide past thin filaments, shortening the sarcomere.

Muscle Tissue and Physiology: Structure and Function of the Muscular System

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