PRACTICE QUESTIONS
1. In monogastric animals, saliva produced during periods of rapid secretion has a higher electrolyte concentration than saliva produced during periods of slow salivary secretion.
From your understanding of salivary gland physiology, which appears to be the most likely explanation?a. During periods of slow salivary secretion, the acinar cells are inactive, and low-electrolyte saliva is secreted by the duct cells.
b. Parasympathetic stimulation of the acinar cells results in the elaboration of a more electrolyte-rich saliva.
c. Gastrin stimulation increases the electrolyte concentration of saliva.
d. During rapid secretion, fluid produced by the acinar cells is exposed to the actions of the duct cells for a shorter time than during slow rates of secretion.
e. Different cell types within the acinus are responsible for salivary production, depending on the type of stimulus.
2. Some nutritionists are experimenting with a drug that increases salivary secretion in cattle. What effect do you think this would have on rumen pH?
a. Increase rumen pH
b. Decrease rumen pH
c. Have no effect on rumen pH
3. Inhibition of the enzyme carbonic anhydrase is likely to have what effect on gastric pH?
a. Decrease gastric pH
b. Increase gastric pH
c. Have no effect on gastric pH
4. Which of the following is not a potential stimulus for gastric acid secretion?
a. Norepinephrine secretion resulting from stimulation of sympathetic nerves.
b. Vagal nerve activity resulting from the sight of food.
c. The presence of undigested protein in the pyloric antrum.
d. Acetylcholine release stimulated by gastric stretch receptors acting on nerves of the ENS.
e. Histamine release from cells in the gastric mucosa.
5. Which of the following is not a natural ligand for receptors in the pancreas?
a. Cholecystokinin
b. Acetylcholine
c. Gastrin
d. Secretin