Question 1

Which type of muscle tissue is shown in the first image (long, cylindrical, multinucleate, and striated fibers)?

Accepted Answer

Skeletal muscle

Question 2

Which connective tissue layer surrounds individual muscle fibers, as shown in the fourth image?

Accepted Answer

Endomysium

Question 3

What is the primary function of the sarcoplasmic reticulum in skeletal muscle fibers?

Accepted Answer

Storing calcium ions ($$\mathrm{Ca$$^{2+}$$})$$

Question 4

Which structure is the functional unit of contraction in a skeletal muscle fiber, as shown in the ninth image?

Accepted Answer

Sarcomere

Question 5

Which protein forms the thick filaments in the sarcomere?

Accepted Answer

Myosin

Question 6

What is the role of acetylcholinesterase at the neuromuscular junction?

Accepted Answer

Breaks down acetylcholine to terminate the signal

Question 7

During the cross-bridge cycle, what event directly causes the myosin head to detach from actin?

Accepted Answer

Binding of ATP to the myosin head

Question 8

Which process is responsible for the rapid replenishment of ATP during the first 10–30 seconds of intense muscle activity?

Accepted Answer

Creatine phosphate system

Question 9

A patient is unable to relax their muscles after exposure to a certain toxin. Which mechanism is most likely affected?

Accepted Answer

Breakdown of acetylcholine by acetylcholinesterase

Question 10

Which muscle fiber type is most resistant to fatigue and is best suited for endurance activities?

Accepted Answer

Slow oxidative fibers

Question 11

Which of the following best describes the 'all-or-none' principle in skeletal muscle contraction?

Accepted Answer

A muscle fiber contracts completely or not at all when stimulated

Question 12

What is the main effect of increasing the frequency of stimulation on a skeletal muscle fiber?

Accepted Answer

Leads to temporal (wave) summation and stronger contractions

Question 13

Which of the following is TRUE regarding the length-tension relationship in skeletal muscle?

Accepted Answer

Optimal tension is produced when there is maximal overlap of actin and myosin without interference

Question 14

Which of the following best explains why cardiac muscle cells do not fatigue as easily as skeletal muscle cells?

Accepted Answer

They have autorhythmicity and a rich blood supply

Question 15

Which structure allows for the rapid transmission of action potentials across the sarcolemma and into the muscle fiber interior?

Accepted Answer

T-tubules

Question 16

A muscle is contracting but not shortening. What type of contraction is this?

Accepted Answer

Isometric contraction

Question 17

Which of the following is a unique feature of cardiac muscle cells visible under the microscope?

Accepted Answer

Intercalated discs

Question 18

Which process is primarily responsible for muscle soreness after intense anaerobic exercise?

Accepted Answer

Accumulation of lactic acid from anaerobic glycolysis

Question 19

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

Accepted Answer

Binds $$\mathrm{Ca$$^{2+}$$}$$ and moves tropomyosin to expose myosin-binding sites on actin

Question 20

A patient with Duchenne muscular dystrophy lacks which important muscle protein?

Accepted Answer

Dystrophin

Chapter 9: Muscles and Muscle Tissue – Comprehensive Study Notes

Study Guide - Practice Questions