Chapter 08: Excitation and Contraction of Smooth Muscle

Chapter 08: Excitation and Contraction of Smooth Muscle

Complete Chapter Questions With Answers

Sample Questions Are Posted Below

1. The contraction of smooth muscle can be attenuated even when intracellular calcium levels are high. This unique ability of smooth muscle can be attributed to variations in the activity of which of the following?

1. Actin
2. Adenosine triphosphate (ATP)
3. Calcium-calmodulin complex
4. Calmodulin
5. Myosin light chain phosphatase

ANS: E

2. Multiple elements can regulate the contraction of smooth muscle, including endocrine, neurocrine, and paracrine factors. This level of diversity in the control of smooth muscle contraction can be attributed to a diversity of which of the following?

1. Actin-myosin arrangement
2. Calcium sensitivities
3. Cell-surface receptors
4. Motor end plates
5. Subneural cleft architecture

ANS: C

3. The effect of autonomic nerve stimulation on smooth muscle contractile behavior depends on the types of receptors on the smooth muscle fibers. Which of the following best describes the effects of acetylcholine and norepinephrine on various types of smooth muscle?

Acetylcholine                          Norepinephrine

1. Contraction only                     Relaxation or contraction
2. Contraction only                     Relaxation only
3. Relaxation only                       Contraction only
4. Relaxation only                       Relaxation only
5. Relaxation or contraction       Contraction only
6. Relaxation or contraction       Relaxation or contraction

ANS: F

4. Unlike skeletal muscle, the contraction of smooth muscle requires which of the following?

1. Activation of ryanodine receptors
2. Phosphorylation of myosin light chains
3. The presence of intracellular calcium
4. Troponin binding of calcium
5. Voltage activation of dihydropyridine receptors

ANS: B

5. Which of the following factors are important for initiating smooth muscle contractions?

Hormones        Paracrine factors         Autonomic nervous system

1. No                   No                               No
2. No                   No                               Yes
3. Yes                  No                               Yes
4. Yes                  Yes                              No
5. Yes                  Yes                              Yes

ANS: E