Question 1

Which of the following best describes the primary function of all types of muscle tissue?

Accepted Answer

To contract and produce muscle tension

Question 2

Which structural property is shared by skeletal, cardiac, and smooth muscle cells?

Accepted Answer

Ability to contract in response to stimulation

Question 3

What is the role of ATP in muscle contraction?

Accepted Answer

ATP hydrolysis provides energy for the power stroke and detachment of myosin from actin

Question 4

Which of the following best explains the striated appearance of skeletal muscle fibers?

Accepted Answer

Alternating arrangement of thick and thin filaments in sarcomeres

Question 5

What is a sarcomere, and why is it considered the functional unit of contraction?

Accepted Answer

A sarcomere is the segment between two Z-discs and is the smallest contractile unit of muscle

Question 6

During the sliding-filament mechanism, which event directly causes muscle shortening?

Accepted Answer

Myosin heads pulling actin filaments toward the M line

Question 7

Which of the following best describes the resting membrane potential of a skeletal muscle fiber?

Accepted Answer

It is the voltage difference across the sarcolemma when the cell is at rest, typically around $$-85\ \mathrm{mV}$$

Question 8

Which sequence correctly traces the events at the neuromuscular junction leading to muscle fiber excitation?

Accepted Answer

Action potential arrives at axon terminal → Synaptic vesicles release ACh → ACh binds to ligand-gated channels → Na$$^+$$ enters muscle fiber → End-plate potential produced

Question 9

Which energy source is primarily used by skeletal muscle to sustain activity for several minutes?

Accepted Answer

Glycolytic catabolism (anaerobic glycolysis)

Question 10

What is the effect of increasing the frequency of stimulation on muscle fiber tension production?

Accepted Answer

It increases tension due to wave summation and can lead to tetanus

Question 11

Which of the following best describes the length-tension relationship in skeletal muscle fibers?

Accepted Answer

Maximum tension is produced when the sarcomere is at optimal resting length

Question 12

Which type of muscle contraction occurs when a muscle develops tension but does not change length?

Accepted Answer

Isometric contraction

Question 13

Which of the following is a characteristic unique to cardiac muscle tissue?

Accepted Answer

Presence of intercalated discs

Question 14

Which protein binds calcium ions to initiate skeletal muscle contraction?

Accepted Answer

Troponin

Question 15

What is the function of acetylcholinesterase at the neuromuscular junction?

Accepted Answer

It breaks down acetylcholine, terminating the signal

Question 16

Which of the following best describes the difference between type I and type II muscle fibers?

Accepted Answer

Type I fibers are slow-twitch and resistant to fatigue; type II fibers are fast-twitch and fatigue quickly

Question 17

Which of the following is a function of myoglobin in muscle fibers?

Accepted Answer

Binds and stores oxygen for aerobic metabolism

Question 18

Which of the following best explains why smooth muscle contraction is slower than skeletal muscle contraction?

Accepted Answer

Smooth muscle uses calmodulin and myosin light-chain kinase instead of troponin

Question 19

Which of the following is a direct result of the power stroke during the crossbridge cycle?

Accepted Answer

The myosin head pivots, pulling the actin filament toward the center of the sarcomere

Muscle Tissue and Physiology: Study Notes for Anatomy & Physiology

Guida di studio - Domande di pratica

Study guide - Flashcard