Question 1

Which muscle shape is depicted in the first image (long, spindle-shaped muscle with tapered ends)?

Accepted Answer

Fusiform

Question 2

The second image shows a muscle arranged in a ring. What is the primary function of this muscle shape?

Accepted Answer

Control of openings (sphincters)

Question 3

The third image shows a muscle with a broad origin and fibers converging to a single tendon. Which muscle shape does this represent?

Accepted Answer

Convergent

Question 4

The fourth image shows a muscle with multiple feather-like fascicles converging on a single tendon. What is this muscle shape called?

Accepted Answer

Multipennate

Question 5

Which of the following is NOT a universal characteristic of muscle tissue?

Accepted Answer

Calcification

Question 6

Which muscle tissue type is voluntary, striated, and multinucleated?

Accepted Answer

Skeletal muscle

Question 7

In the histology images, which muscle type is identified by striations, branching fibers, and intercalated discs?

Accepted Answer

Cardiac muscle

Question 8

Which structure connects muscle to bone and is visible as a white band at the end of the muscle in several images?

Accepted Answer

Tendon

Question 9

Which muscle type is responsible for peristalsis and is found in the walls of hollow organs?

Accepted Answer

Smooth muscle

Question 10

Which of the following best describes the role of the sodium/potassium pump in muscle fibers?

Accepted Answer

It establishes the resting membrane potential by pumping 3 Na+ out and 2 K+ in.

Question 11

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

Accepted Answer

Tropomyosin

Question 12

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

Accepted Answer

Storing and releasing calcium ions

Question 13

During the sliding filament theory of muscle contraction, which of the following does NOT change length?

Accepted Answer

A band

Question 14

Which of the following best explains why rigor mortis occurs after death?

Accepted Answer

Calcium leaks into the sarcoplasm and ATP is unavailable to break cross-bridges.

Question 15

Which of the following is the correct sequence of events in the cross-bridge cycle?

Accepted Answer

Myosin binds actin, powerstroke, myosin releases actin, myosin recharges

Question 16

Which energy source provides the most ATP for sustained muscle contraction?

Accepted Answer

Aerobic cellular respiration

Question 17

A patient receives Botox injections to reduce facial wrinkles. Which step in the excitation-contraction cycle is directly inhibited by Botox?

Accepted Answer

Release of acetylcholine from the motor neuron

Question 18

Which of the following best describes a motor unit?

Accepted Answer

A motor neuron and all the muscle fibers it innervates

Question 19

Which type of contraction allows you to hold a heavy object still without moving it?

Accepted Answer

Isometric contraction

Question 20

Which muscle is the prime mover (agonist) in elbow flexion?

Accepted Answer

Biceps brachii

The Muscular System: Anatomy, Histology, and Physiology

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