Question 1

Which property of muscle tissue most directly allows it to convert chemical energy into mechanical energy for movement?

Accepted Answer

Contractility

Question 2

You are examining a tissue sample under a microscope and observe that it is striated and multinucleated. Which type of muscle tissue are you most likely observing?

Accepted Answer

Skeletal muscle

Question 3

Which of the following statements about cardiac muscle is correct?

Accepted Answer

It is involuntary and striated

Question 4

Which connective tissue layer directly surrounds individual muscle fibers?

Accepted Answer

Endomysium

Question 5

In the context of muscle structure, what is a fascicle?

Accepted Answer

A bundle of muscle fibers

Question 6

Which of the following is the smallest contractile unit of a muscle?

Accepted Answer

Sarcomere

Question 7

During muscle contraction, which filament is pulled toward the center of the sarcomere?

Accepted Answer

Actin

Question 8

Which protein blocks the myosin binding sites on actin in a relaxed muscle?

Accepted Answer

Tropomyosin

Question 9

What is the primary role of calcium ions ($$\mathrm{Ca$$^{2+}$$}) in $$muscle contraction?

Accepted Answer

To bind to troponin, causing tropomyosin to move and expose myosin binding sites

Question 10

Which of the following best describes the sequence of events in excitation-contraction coupling?

Accepted Answer

Action potential → Ca$$^{2+}$$ release → Troponin binds Ca$$^{2+}$$ → Tropomyosin moves → Myosin binds actin

Question 11

If a muscle completely runs out of ATP during contraction, what would happen?

Accepted Answer

After the power stroke, the myosin would remain bound to the actin

Question 12

Which region of the sarcomere contains only thick filaments and no thin filaments?

Accepted Answer

H Zone

Question 13

Which of the following is NOT found in the A band of a sarcomere?

Accepted Answer

Z Disc

Question 14

Which of the following best describes the role of the sarcoplasmic reticulum in muscle contraction?

Accepted Answer

It stores and releases calcium ions ($$\mathrm{Ca$$^{2+}$$})$$

Question 15

During an action potential in a muscle fiber, which ion moves into the cell to cause depolarization?

Accepted Answer

Na$$^+$$

Question 16

Which attachment site of a muscle is typically stationary during contraction?

Accepted Answer

Origin

Question 17

The flexor carpi ulnaris muscle adducts and flexes the hand at the wrist. It attaches to both the humerus and the base of the 5th metacarpal. Which attachment is the origin?

Accepted Answer

Humerus

Question 18

Which of the following best describes the power stroke in the cross-bridge cycle?

Accepted Answer

Myosin pulling the actin filament

Question 19

Which protein is responsible for the elasticity of the sarcomere, helping it return to its original length after contraction?

Accepted Answer

Titin

Question 20

Which of the following would most likely be observed in the sarcomere of an individual with myosin storage myopathy?

Accepted Answer

The thick filament would form protein clumps

The Muscular System: Structure, Function, and Contraction

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