GI GI Anatomy and Physiology 2

Question 1

Peyer's patches, lymphoid aggregates important for gut immunity, are found predominantly in which GI segment?

Accepted Answer

Ileum

Answer

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?

Accepted Answer

Secretin

Answer

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?

Accepted Answer

Common bile duct and main pancreatic duct

Answer

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?

Accepted Answer

Enterokinase (enteropeptidase)

Answer

Enterokinase (enteropeptidase), a brush-border enzyme, cleaves the activation peptide from trypsinogen to generate trypsin.

Question 5

The crypt of Lieberkühn contains which cell type that acts as the intestinal stem cell niche regulator?

Accepted Answer

Paneth cells

Answer

Paneth cells reside at the base of intestinal crypts, secreting defensins and supporting the local stem cell microenvironment.

Gastrointestinal GI Practice Practice Test