PRACTICE QUESTIONS

1. WQiich Statenicnt is the most accurate anatomical descrip­tion of the enteric nervous system (ENS) of the gut?

a. Intrinsic neuronal fibers and their cell bodies are diffusely spread throughout the length and thickness of the stomach and intestine.

b. Intrinsic neuronal fibers traverse the length of the stomach and intestine in discrete nerve bundles.

c. Intrinsic neuronal cell bodies are aggregated in a discrete “gut brain” that is positioned near the pylorus.

d. Intrinsic neuronal cell bodies lie in discrete planes within the thickness of the gut wall and are diffusely distributed throughout its length.

e. Intrinsic neuronal fibers exist only in the longi­tudinal muscle layer of the stomach and intestine.

2. Which statement is true with regard to the para­sympathetic fibers that innervate the cells of the ENS?

a. The fibers exit the central nervous system from lumbar segments of the spinal cord.

b. The fibers have vasoactive intestinal peptide as a neurotransmitter.

c. The fibers are inhibitory.

d. The fibers are preganglionic.

e. There are no parasympathetic fibers that innervate cells of the ENS.

3. Which statement is true with regard to the GI endocrine cells?

a. Secretory activity is influenced by the luminal contents of the gut.

b. Hormones are secreted directly into the gut lumen and affect the activity of glands “downstream” from the point of secretion.

c. The secretory products of the GI endocrine cells are steroid hormones.

d. Each GI endocrine cell can produce many different types of hormones, depending on the stimulus applied to it.

4. Which of the following statements concerning the neurohumoral regulatory molecules of the gut is true?

a. They are all peptides.

b. They all are excitatory and increase the rate of gut motility and secretion.

c. GI neurohumoral regulatory molecules and their analogues and antagonists will probably become important agents of therapy in GI disease.

d. All the above

5. Which of the following conditions in the gut would NOT provide direct sensory input to the ENS?

a. Changes in luminal pressure resulting in changes in tension of gut wall musculature.

b. Changes in luminal pH.

c. Changes in luminal osmotic pressure.

d. Changes in the rate of ingesta flow.

6. Which of the following neurocrine transmitter molecules is most consistently excitatory relative to gut functions?

a. Somatostatin

b. Acetylcholine

c. Vasoactive intestinal peptide (VIP)

d. ATP

7. All neurocrine transmitter molecules are peptides.

a. True

b. False

8. The conscious sensation of pain due to excessive distention of a segment of the gut arises from afferent impulses travel­ing to the brain through:

a. the myenteric plexus.

b. the submucosal plexus.

c. the vagus nerve.

d. the splanchnic nerves.

9. Which anatomical description best applies to the organiza­tion of the GI endocrine cells?

a. Cells arranged into small islets in the intestinal submucosa.

b. Cells distributed diffusely throughout the mucosa of the GI tract.

c. Cells arranged into discrete glands situated between the circular and longitudinal muscle layers.

d. Cells distributed diffusely throughout the sub­mucosa of the GI tract.

10. The influence of the Gl mucosal immune system on gut functions is mediated by:

a. the CNS.

b. the direct action of cytokines on gut smooth muscle and glands.

c. the interaction of cytokines with the ENS and GI endocrine/paracrine cells.

d. the direct action of T cells on gut smooth muscle and glands.