Question 1

Which type of muscle tissue is shown in the first image, and what is a unique feature of this tissue?

Accepted Answer

Cardiac muscle; it is striated and has intercalated discs.

Question 2

Which connective tissue layer surrounds individual muscle fibers?

Accepted Answer

Endomysium

Question 3

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

Accepted Answer

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

Question 4

During the sliding filament mechanism, what happens to the length of the thick and thin filaments?

Accepted Answer

Neither filament changes length

Question 5

Which protein directly covers the myosin-binding sites on actin in a relaxed muscle?

Accepted Answer

Tropomyosin

Question 6

A patient is given curare during surgery. What is the expected effect at the neuromuscular junction?

Accepted Answer

Blockage of acetylcholine receptors, causing paralysis

Question 7

Which metabolic pathway provides the majority of ATP for a marathon runner?

Accepted Answer

Aerobic cellular respiration

Question 8

What is the role of acetylcholinesterase at the neuromuscular junction?

Accepted Answer

Breaks down acetylcholine to terminate the signal

Question 9

Which type of muscle contraction occurs when you hold a heavy object steady without moving it?

Accepted Answer

Isometric contraction

Question 10

A muscle fiber is stimulated before it has completely relaxed from a previous stimulus, resulting in a stronger contraction. What is this phenomenon called?

Accepted Answer

Wave summation

Question 11

Which muscle fiber type is most abundant in the postural muscles of the back and neck?

Accepted Answer

Slow oxidative fibers

Question 12

What is the main cause of rigor mortis after death?

Accepted Answer

Lack of ATP prevents detachment of myosin from actin

Question 13

Which of the following best describes the latent period of a muscle twitch?

Accepted Answer

The time between stimulus application and the beginning of contraction

Question 14

If a muscle is stretched beyond its optimal length before contraction, what happens to the force produced?

Accepted Answer

Force decreases due to fewer crossbridges

Question 15

Which of the following is a regulatory protein in muscle contraction?

Accepted Answer

Troponin

Question 16

A patient with myasthenia gravis is treated with neostigmine. What is the mechanism of action?

Accepted Answer

Inhibits acetylcholinesterase, increasing acetylcholine at the NMJ

Question 17

Which of the following best explains why muscle tone is important for maintaining blood pressure?

Accepted Answer

It maintains partial contraction of smooth muscle in blood vessel walls

Question 18

Which of the following is a characteristic of fast glycolytic muscle fibers?

Accepted Answer

White color, few mitochondria, and anaerobic metabolism

Question 19

What is the effect of anabolic steroids on muscle tissue?

Accepted Answer

Increase muscle size, strength, and endurance, but with significant side effects

Question 20

Which of the following best describes the role of titin in the sarcomere?

Accepted Answer

It provides elasticity and helps anchor thick filaments

Muscle Tissue: Structure, Function, and Physiology

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