Question 1

Which connective tissue sheath directly surrounds an individual muscle fiber?

Accepted Answer

Endomysium

Question 2

During a muscle contraction, which structure is responsible for transmitting the action potential deep into the muscle fiber?

Accepted Answer

T tubule

Question 3

A patient is unable to flex their forearm at the elbow. Which muscle is most likely impaired?

Accepted Answer

Biceps brachii

Question 4

Which of the following best describes the function of the perimysium?

Accepted Answer

Surrounds bundles of muscle fibers (fascicles)

Question 5

If a motor neuron innervates 10 muscle fibers, what is the size of the motor unit?

Accepted Answer

$$10$$

Question 6

Which protein forms the thick filaments in a sarcomere?

Accepted Answer

Myosin

Question 7

A muscle twitch consists of three phases. Which phase immediately follows the latent period?

Accepted Answer

Contraction period

Question 8

Which abdominal muscle is oriented horizontally and is primarily responsible for compressing the abdominal contents?

Accepted Answer

Transversus abdominis

Question 9

If the threshold stimulus for a muscle fiber is $$0.5\,V$$ and a stimulus of $$0.3\,V is $$applied, what will happen?

Accepted Answer

There will be no contraction

Question 10

Which muscle is the prime mover for shoulder abduction?

Accepted Answer

Deltoid

Question 11

Which of the following movements describes turning the palm upward?

Accepted Answer

Supination

Question 12

A patient presents with difficulty elevating their scapula. Which muscle is most likely affected?

Accepted Answer

Levator scapulae

Question 13

Which structure is the site of communication between a motor neuron and a muscle fiber?

Accepted Answer

Neuromuscular junction

Question 14

Which muscle is responsible for compressing the cheeks, as in blowing a trumpet?

Accepted Answer

Buccinator

Question 15

Which muscle is the antagonist to the biceps brachii during elbow flexion?

Accepted Answer

Triceps brachii

Question 16

If a muscle is stimulated at a frequency that does not allow complete relaxation between stimuli, what is this phenomenon called?

Accepted Answer

Incomplete tetanus

Question 17

Which of the following is the correct order of connective tissue sheaths from outermost to innermost?

Accepted Answer

Epimysium, Perimysium, Endomysium

Question 18

Which muscle is primarily responsible for dorsiflexion of the foot?

Accepted Answer

Tibialis anterior

Question 19

A patient has a lesion affecting the sarcolemma of their muscle fibers. Which function is most likely impaired?

Accepted Answer

Transmission of action potentials along the muscle fiber

Question 20

Which equation best represents the relationship between force generated by a muscle and the number of motor units recruited?

Accepted Answer

$$F \propto n$$

Muscular System: Structure, Function, and Physiology (Biol 111 Lab 6 Study Notes)

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