Q: Which of the following equations correctly calculates 75% of a maximal clench force of 60 kg?

$$75\% \times 60\ \mathrm{kg} = 0.75 \times 60\ \mathrm{kg} = 45\ \mathrm{kg}$$

Question 1

Which of the following best describes the structural difference between skeletal, cardiac, and smooth muscle cells?

Accepted Answer

Skeletal muscle cells are striated and multinucleate; cardiac muscle cells are striated, branched, and uninucleate; smooth muscle cells are non-striated and uninucleate.

Question 2

A muscle is named 'biceps brachii.' Based on muscle naming conventions, what does 'biceps' indicate?

Accepted Answer

The muscle has two origins.

Question 3

Which connective tissue layer directly surrounds individual muscle fibers?

Accepted Answer

Endomysium

Question 4

During a muscle contraction, which region of the sarcomere shortens?

Accepted Answer

I band

Question 5

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

Accepted Answer

Cardiac muscle has intrinsic autorhythmicity and a high density of mitochondria.

Question 6

A patient is unable to extend their wrist. Which muscle is most likely impaired?

Accepted Answer

Extensor carpi radialis

Question 7

Which of the following equations correctly calculates 75% of a maximal clench force of 60 kg?

Accepted Answer

$$75\% 	imes 60\ \mathrm{kg} = 0.75 	imes 60\ \mathrm{kg} = 45\ \mathrm{kg}$$

Question 8

Which muscle functional group is primarily responsible for producing a specific movement?

Accepted Answer

Prime mover (agonist)

Question 9

What is the main function of intercalated discs in cardiac muscle?

Accepted Answer

They allow rapid transmission of electrical impulses between cells.

Question 10

Which of the following best describes an isometric muscle contraction?

Accepted Answer

Muscle tension increases but the muscle does not shorten.

Question 11

A muscle named 'rectus abdominis' is named for which characteristic?

Accepted Answer

The direction of its fibers (straight)

Question 12

Which of the following is a real-life example of multiple motor unit recruitment (MMUR)?

Accepted Answer

Gradually increasing grip strength when opening a tightly sealed jar.

Question 13

Which of the following best explains the 'all-or-none' rule in muscle contraction?

Accepted Answer

All muscle fibers in a motor unit contract completely when stimulated above threshold.

Question 14

Which of the following is NOT a characteristic of smooth muscle?

Accepted Answer

Striated appearance

Question 15

A muscle is attached to a bone by a cord-like structure. What is this structure called?

Accepted Answer

Tendon

Question 16

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

Accepted Answer

It is the time required for excitation-contraction coupling to occur before contraction begins.

Question 17

Which of the following would most likely result in fused (complete) tetanus in a skeletal muscle?

Accepted Answer

High-frequency stimulation with no relaxation between contractions.

Question 18

Which muscle is named for both its origin and insertion?

Accepted Answer

Sternocleidomastoid

Question 19

Which of the following best describes the role of a fixator muscle?

Accepted Answer

It stabilizes the origin of the prime mover.

Question 20

During an EMG experiment, a student’s maximal clench force is 40 kg. What force should they generate to reach 50% of maximal clench force?

Accepted Answer

$$50\% 	imes 40\ \mathrm{kg} = 0.5 	imes 40\ \mathrm{kg} = 20\ \mathrm{kg}$$

Muscles and Muscle Tissue: Structure, Function, and Electromyography

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