Question 1

Which of the following is a unique characteristic of cardiac muscle tissue compared to skeletal and smooth muscle tissues?

Accepted Answer

It contracts at a steady rate due to its own pacemaker.

Question 2

A patient is experiencing muscle fatigue after intense exercise. Which of the following best explains why ATP is required for muscle relaxation?

Accepted Answer

ATP is required to pump calcium ions back into the sarcoplasmic reticulum.

Question 3

During the sliding filament model of contraction, which event directly causes the sarcomere to shorten?

Accepted Answer

Myosin heads pull actin filaments toward the M line.

Question 4

Which connective tissue sheath surrounds individual muscle fibers?

Accepted Answer

Endomysium

Question 5

A marathon runner relies primarily on which pathway for ATP production during the majority of the race?

Accepted Answer

Aerobic respiration

Question 6

Which of the following best describes the function of the T tubules in skeletal muscle fibers?

Accepted Answer

They increase the muscle fiber's surface area and help transmit action potentials deep into the cell.

Question 7

A patient with a genetic defect in the protein titin would most likely experience which of the following symptoms?

Accepted Answer

Excessive stretching and poor recoil of muscle fibers

Question 8

Which of the following equations correctly represents the direct phosphorylation of ADP by creatine phosphate in muscle cells?

Accepted Answer

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

Question 9

Which of the following best explains why smooth muscle can maintain contractions for long periods with minimal energy expenditure?

Accepted Answer

Smooth muscle has a latch-bridge mechanism that allows it to maintain tension with low ATP consumption.

Question 10

A muscle is stimulated at increasing frequencies, and the tension increases until it reaches a plateau with no visible relaxation between stimuli. What is this phenomenon called?

Accepted Answer

Complete (fused) tetanus

Question 11

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

Accepted Answer

Action potential arrives at axon terminal → Voltage-gated Ca$$^{2+}$$ channels open → ACh released into synaptic cleft → ACh binds to receptors on sarcolemma → Na$$^+$$ enters muscle fiber

Question 12

Which of the following best describes the 'size principle' of motor unit recruitment?

Accepted Answer

Smaller motor units are recruited first, followed by larger ones as stimulus intensity increases.

Question 13

A patient is unable to maintain posture and experiences frequent falls. Which muscle function is most likely impaired?

Accepted Answer

Maintenance of posture and body position

Question 14

Which of the following best explains why muscle tone is important even when a muscle is at rest?

Accepted Answer

It keeps muscles firm, healthy, and ready to respond to stimulation.

Question 15

Which of the following is true regarding the difference between isometric and isotonic muscle contractions?

Accepted Answer

Isometric contractions generate tension without changing muscle length, while isotonic contractions result in muscle shortening or lengthening.

Question 16

Which of the following best describes the role of calcium ions ($$\mathrm{Ca}^{2+}) in $$skeletal muscle contraction?

Accepted Answer

They bind to troponin, causing a conformational change that moves tropomyosin away from actin's binding sites.

Question 17

A sprinter uses which energy system predominantly during the first 10 seconds of a 100-meter dash?

Accepted Answer

Direct phosphorylation of ADP by creatine phosphate

Question 18

Which of the following best explains why lactic acid accumulates in muscles during intense exercise?

Accepted Answer

Aerobic respiration is unable to keep up with ATP demand, so pyruvic acid is converted to lactic acid in the absence of sufficient oxygen.

Question 19

Which of the following is a function of synergist muscles?

Accepted Answer

They add extra force to a movement and reduce unnecessary movements.

Question 20

Which of the following best describes the role of acetylcholinesterase at the neuromuscular junction?

Accepted Answer

It breaks down acetylcholine in the synaptic cleft, terminating the signal.

Muscles and Muscle Tissue: Structure, Function, and Types

Study Guide - Practice Questions

Study Guide - Flashcards