Question 1

Which of the following best describes the arrangement of actin and myosin in smooth muscle cells?

Accepted Answer

Arranged in diagonal chains anchored at dense bodies

Question 2

A patient is experiencing difficulty with peristalsis in the digestive tract. Which smooth muscle layer is primarily responsible for shortening the organ during contraction?

Accepted Answer

Longitudinal layer

Question 3

Which of the following is a key structural difference between skeletal and smooth muscle cells?

Accepted Answer

Smooth muscle cells have a single nucleus and no myofibrils

Question 4

Which type of smooth muscle is found in the iris of the eye and allows for precise control of pupil size?

Accepted Answer

Multiunit smooth muscle

Question 5

What is the primary function of gap junctions in unitary smooth muscle?

Accepted Answer

To allow nerve signals to spread directly from one cell to the next

Question 6

Which of the following best explains why smooth muscle can maintain contraction for long periods with minimal energy use?

Accepted Answer

Myosin heads remain attached to actin in a latch state

Question 7

A drug that blocks the function of caveolae in smooth muscle cells would most likely interfere with which process?

Accepted Answer

Transmission of electrical signals and opening of Ca$$^{2+}$$ channels

Question 8

Which of the following equations best represents the energy usage difference between skeletal and smooth muscle during sustained contraction?

Accepted Answer

$$E_{smooth} \u003c E_{skeletal}$$

Question 9

Which of the following is NOT a location where unitary smooth muscle is typically found?

Accepted Answer

Large blood vessels

Question 10

A patient has a disorder affecting the arrector pili muscles of the skin. Which type of smooth muscle is most likely involved?

Accepted Answer

Multiunit smooth muscle

Question 11

Which connective tissue layer is found covering individual smooth muscle cells?

Accepted Answer

Endomysium

Question 12

Which of the following best describes the contraction pattern of smooth muscle cells?

Accepted Answer

Corkscrew-like twisting due to diagonal actin and myosin arrangement

Question 13

Which of the following statements about skeletal muscle is correct?

Accepted Answer

It contains sarcomeres and multiple nuclei per cell

Question 14

Which structure in smooth muscle cells serves a similar function to T-tubules in skeletal muscle?

Accepted Answer

Caveolae

Question 15

A researcher is studying a muscle that contracts as a single unit due to the presence of gap junctions. Which type of muscle is being studied?

Accepted Answer

Unitary smooth muscle

Question 16

Which of the following best explains why multiunit smooth muscle allows for more precise control than unitary smooth muscle?

Accepted Answer

Each cell receives its own nerve ending

Question 17

Which of the following is a correct comparison between skeletal and smooth muscle contraction?

Accepted Answer

Skeletal muscle contracts rapidly and powerfully, smooth muscle contracts slowly and resists fatigue

Question 18

Which of the following best describes the role of the circular layer of smooth muscle in the intestine?

Accepted Answer

Constricts the interior of the organ during contraction

Question 19

Which of the following is a real-life example of multiunit smooth muscle function?

Accepted Answer

Precise dilation and constriction of the pupil in response to light

Question 20

Which of the following best explains why smooth muscle is able to maintain tone in blood vessels over long periods?

Accepted Answer

Smooth muscle cells can enter a latch state, maintaining contraction with minimal ATP

Smooth Muscle Anatomy and Contraction: Structure, Types, and Comparison with Skeletal Muscle

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