Question 1

Which of the following best describes the primary function of bile produced by the liver?

Accepted Answer

Bile neutralizes stomach acid and emulsifies fats, aiding in their digestion and absorption.

Question 2

A patient presents with severe abdominal pain and rebound tenderness. Imaging reveals leakage of intestinal contents into the peritoneal cavity. What is the most likely diagnosis?

Accepted Answer

Peritonitis

Question 3

Which layer of the digestive tract is primarily responsible for peristalsis and segmentation?

Accepted Answer

Muscularis externa

Question 4

During the cephalic phase of gastric secretion, which nerve carries parasympathetic signals to the stomach to stimulate secretion?

Accepted Answer

Vagus nerve

Question 5

Which of the following is a function of the large intestine?

Accepted Answer

Absorption of water and salts, and formation of feces

Question 6

A patient with a history of drastic dieting develops severe right upper quadrant pain after a fatty meal. Imaging shows a blockage in the cystic duct. What is the most likely cause?

Accepted Answer

Gallstones (cholelithiasis)

Question 7

Which of the following best explains why the addition of fluoride to drinking water reduces dental caries?

Accepted Answer

Fluoride increases the hardness of enamel, making it more resistant to acid produced by bacteria.

Question 8

Which of the following hormones is released by the duodenum in response to acidic chyme and inhibits gastric secretion?

Accepted Answer

Secretin

Question 9

Which of the following is the correct sequence of events during swallowing (deglutition)?

Accepted Answer

Voluntary phase → Pharyngeal phase → Esophageal phase

Question 10

Which of the following best describes the role of the enteric nervous system in the digestive tract?

Accepted Answer

It coordinates local reflexes and regulates peristalsis and secretion independently of the CNS.

Question 11

A patient with chronic GERD is prescribed a proton pump inhibitor. What is the mechanism of action of this drug?

Accepted Answer

It inhibits the H$$^+/K$^+$$ ATPase pump in parietal cells, reducing gastric acid secretion.

Question 12

Which of the following structures increases the surface area of the small intestine for absorption?

Accepted Answer

Villi, microvilli, and plicae circulares

Question 13

Which of the following best describes the process of peristalsis?

Accepted Answer

A wave of circular smooth muscle contraction behind the bolus propels it forward, while relaxation ahead allows expansion.

Question 14

Which of the following is a function of the hepatocytes in the liver?

Accepted Answer

Detoxification of ammonia by converting it to urea

Question 15

Which of the following best explains why a patient with a blocked common bile duct may develop steatorrhea (fatty stools)?

Accepted Answer

Bile cannot reach the intestine to emulsify fats, impairing fat digestion and absorption.

Question 16

Which of the following is the correct formula for the conversion of carbon dioxide and water to carbonic acid in parietal cells, catalyzed by carbonic anhydrase?

Accepted Answer

$$ \mathrm{CO_2 + H_2O \xrightarrow{carbonic\ anhydrase} H_2CO_3} $$

Question 17

Which of the following best describes the function of chylomicrons in lipid absorption?

Accepted Answer

They transport absorbed triglycerides from the intestinal epithelial cells into the lymphatic system.

Question 18

A patient with a deficiency in intrinsic factor is most likely to develop which of the following conditions?

Accepted Answer

Pernicious anemia due to impaired vitamin B12 absorption

Question 19

Which of the following statements about the absorption of water in the digestive tract is correct?

Accepted Answer

Water can move in either direction across the wall of the small intestine depending on osmotic gradients.

The Digestive System: Structure, Function, and Regulation

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