Question 1

Which of the following best explains why intrinsic factor secretion by parietal cells is essential for life?

Accepted Answer

It is required for the absorption of vitamin B12, which is necessary for erythropoiesis.

Question 2

A patient with pernicious anemia most likely has a deficiency in which of the following?

Accepted Answer

Intrinsic factor

Question 3

Which chemical is the most potent stimulator of acid secretion by parietal cells in the stomach?

Accepted Answer

Histamine

Question 4

During the gastric phase of gastric secretion, which of the following events occurs?

Accepted Answer

Both acetylcholine and gastrin stimulate histamine secretion, increasing acid production.

Question 5

Which of the following best describes the mechanism by which parietal cells secrete hydrochloric acid ($$\mathrm{HCl}$$)?

Accepted Answer

The $$\mathrm{H^+/K^+}$$ ATPase pumps $$\mathrm{H^+}$$ into the lumen in exchange for $$\mathrm{K^+}$$, while $$\mathrm{Cl^-}$$ diffuses into the lumen to combine with $$\mathrm{H^+}.$$

Question 6

Which of the following is a direct result of the 'alkaline tide' after a meal?

Accepted Answer

Increased $$\mathrm{$$HCO_3$$^-} in $$the blood leaving the stomach

Question 7

Which of the following best describes the activation of pepsinogen in the stomach?

Accepted Answer

Pepsinogen is converted to pepsin by hydrochloric acid ($$\mathrm{HCl}) in $$the stomach lumen.

Question 8

Which of the following is the primary stimulus for pepsinogen secretion from chief cells?

Accepted Answer

Acetylcholine (ACh)

Question 9

Which of the following best explains why only small particles and liquids pass through the pyloric valve into the duodenum?

Accepted Answer

Peristaltic contractions are most vigorous near the pylorus, forcing larger particles backward into the stomach (retropulsion).

Question 10

A patient has a meal high in fat. Which of the following will occur in response to the entry of fatty chyme into the duodenum?

Accepted Answer

Release of cholecystokinin (CCK), which stimulates gallbladder contraction and pancreatic enzyme secretion.

Question 11

Which of the following is the main digestive function of bile produced by the liver?

Accepted Answer

Emulsification of fats to increase surface area for lipase action.

Question 12

Which of the following best describes the enterohepatic circulation of bile salts?

Accepted Answer

Bile salts are reabsorbed in the ileum and returned to the liver via the hepatic portal vein.

Question 13

Which of the following is a likely consequence of gallstone formation blocking the cystic duct?

Accepted Answer

Impaired delivery of bile to the duodenum, leading to fat malabsorption.

Question 14

Which of the following is the main function of bicarbonate ions secreted by the pancreas?

Accepted Answer

Neutralization of acidic chyme entering the duodenum.

Question 15

Which enzyme is responsible for activating trypsinogen to trypsin in the small intestine?

Accepted Answer

Enteropeptidase

Question 16

Which hormone is released in response to acidic chyme entering the duodenum and stimulates the secretion of a bicarbonate-rich fluid from the pancreas?

Accepted Answer

Secretin

Question 17

Which of the following structural modifications of the small intestine increases its surface area for absorption the most?

Accepted Answer

Microvilli

Question 18

Which cell type in the small intestine is responsible for secreting antimicrobial agents such as defensins and lysozyme?

Accepted Answer

Paneth cells

Question 19

A patient with a resected distal ileum is at risk for which of the following complications?

Accepted Answer

Decreased recycling of bile salts, leading to fat malabsorption.

Question 20

Which of the following best describes the role of the enterogastric reflex?

Accepted Answer

It inhibits gastric secretion and motility when the duodenum is distended or contains fatty, acidic, or hypertonic chyme.

Digestive System Part 2: The Stomach, Liver, Gallbladder, Pancreas, and Small Intestine

Study Guide - Practice Questions

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