GI GI Anatomy and Physiology 2 — Questions and Answers
Question 1: Peyer's patches, lymphoid aggregates important for gut immunity, are found predominantly in which GI segment?
- Duodenum
- Jejunum
- Ileum (Correct answer)
- Cecum
Correct answer: Ileum
Peyer's patches are concentrated in the distal ileum where they sample luminal antigens via specialized M cells.
Question 2: Which hormone, released by S cells in the duodenum, stimulates pancreatic bicarbonate secretion?
- Gastrin
- Cholecystokinin
- Secretin (Correct answer)
- Motilin
Correct answer: Secretin
Secretin is released in response to acid entering the duodenum and stimulates pancreatic duct cells to secrete bicarbonate-rich fluid.
Question 3: The hepatopancreatic ampulla (ampulla of Vater) is the site where which two ducts join before entering the duodenum?
- Hepatic duct and pancreatic duct
- Cystic duct and common bile duct
- Common bile duct and main pancreatic duct (Correct answer)
- Hepatic duct and cystic duct
Correct answer: Common bile duct and main pancreatic duct
The common bile duct and the main pancreatic duct (of Wirsung) unite at the ampulla of Vater before emptying into the duodenum.
Question 4: Which enzyme converts trypsinogen to active trypsin in the duodenum?
- Enterokinase (enteropeptidase) (Correct answer)
- Chymotrypsin
- Elastase
- Carboxypeptidase A
Correct answer: Enterokinase (enteropeptidase)
Enterokinase (enteropeptidase), a brush-border enzyme, cleaves the activation peptide from trypsinogen to generate trypsin.
Question 5: The crypt of LieberkĂĽhn contains which cell type that acts as the intestinal stem cell niche regulator?
- Goblet cells
- Enterocytes
- Paneth cells (Correct answer)
- Enteroendocrine cells
Correct answer: Paneth cells
Paneth cells reside at the base of intestinal crypts, secreting defensins and supporting the local stem cell microenvironment.
Question 6: What is the approximate transit time of contents through the entire colon in a healthy adult?
- 2–4 hours
- 6–12 hours
- 24–72 hours (Correct answer)
- 5–7 days
Correct answer: 24–72 hours
Normal colonic transit takes approximately 24 to 72 hours, though this can vary widely with diet and activity.
GI GI Anatomy and Physiology 2
Peyer's patches, lymphoid aggregates important for gut immunity, are found predominantly in which GI segment?