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Gastrointestinal and Hepatobiliary System
Case Study | 2026 Update with complete
solutions.
1. The primary function of the lower esophageal sphincter (LES) is
to:
A) Propel food into the stomach
B) Prevent reflux of gastric contents into the esophagus
C) Secrete intrinsic factor
D) Regulate gastric emptying
Answer: B
Rationale: The LES acts as a physiological barrier to prevent
gastroesophageal reflux. Failure of LES tone leads to GERD.
Q2. Which cells of the stomach secrete hydrochloric acid?
A) Chief cells
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B) G cells
C) Parietal cells
D) Mucous cells
Answer: C
Rationale: Parietal cells secrete HCl and intrinsic factor. Chief
cells secrete pepsinogen; G cells secrete gastrin.
Q3. The primary site of nutrient absorption is the:
A) Stomach
B) Small intestine
C) Large intestine
D) Rectum
Answer: B
Rationale: The small intestine (duodenum, jejunum, ileum) absorbs
most carbohydrates, proteins, fats, vitamins, and minerals.
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Q4. Which segment of the small intestine is responsible for the
absorption of vitamin B12 and bile salts?
A) Duodenum
B) Jejunum
C) Ileum
D) Cecum
Answer: C
Rationale: The terminal ileum is the specific site for vitamin B12
(with intrinsic factor) and bile salt reabsorption.
Q5. The portal vein is formed by the union of the:
A) Hepatic artery and splenic vein
B) Superior mesenteric vein and splenic vein
C) Inferior mesenteric vein and gastric vein
D) Renal vein and hepatic vein
Gastrointestinal and Hepatobiliary System
Case Study | 2026 Update with complete
solutions.
1. The primary function of the lower esophageal sphincter (LES) is
to:
A) Propel food into the stomach
B) Prevent reflux of gastric contents into the esophagus
C) Secrete intrinsic factor
D) Regulate gastric emptying
Answer: B
Rationale: The LES acts as a physiological barrier to prevent
gastroesophageal reflux. Failure of LES tone leads to GERD.
Q2. Which cells of the stomach secrete hydrochloric acid?
A) Chief cells
,Page 2 of 24
B) G cells
C) Parietal cells
D) Mucous cells
Answer: C
Rationale: Parietal cells secrete HCl and intrinsic factor. Chief
cells secrete pepsinogen; G cells secrete gastrin.
Q3. The primary site of nutrient absorption is the:
A) Stomach
B) Small intestine
C) Large intestine
D) Rectum
Answer: B
Rationale: The small intestine (duodenum, jejunum, ileum) absorbs
most carbohydrates, proteins, fats, vitamins, and minerals.
, Page 3 of 24
Q4. Which segment of the small intestine is responsible for the
absorption of vitamin B12 and bile salts?
A) Duodenum
B) Jejunum
C) Ileum
D) Cecum
Answer: C
Rationale: The terminal ileum is the specific site for vitamin B12
(with intrinsic factor) and bile salt reabsorption.
Q5. The portal vein is formed by the union of the:
A) Hepatic artery and splenic vein
B) Superior mesenteric vein and splenic vein
C) Inferior mesenteric vein and gastric vein
D) Renal vein and hepatic vein
