TBL17 - Stomach

Question 1

What do macroscopic folds of mucosa and submucosa form?

Answer 1

Macroscopic folds of mucosa and submucosa form rugae that flatten as the stomach fills

Question 2

What does the serosa cover? What does it represent?

Answer 2

1) A serosa covers the muscularis externa
2) It represents the adventitia covered by visceral peritoneum i.e., intraperitoneal GI tract viscera have a serosa and retro-peritoneal intestinal viscera have an adventitia

Question 3

What does simple columnar epithelium do in the stomach? What populates the gastric glands?

Answer 3

1) The simple columnar epithelium regularly dips to join long gastric glands that extend in the lamina propria to the muscularis mucosae
2) Mucous cells, parietal cells, and chief cells populate the gastric glands

Question 4

What types of cells do glands in the fundus and body of the stomach contain? What kinds of cells do glands in the pylorus contain?

Answer 4

Glands in the fundus and body of the stomach contain all three cell types while glands in the pylorus contain only mucous cells

Question 5

What do parietal cells do and what does this form in the glandular lumens? What do chief cells secrete and what does this do?

Answer 5

1) Parietal cells actively transport hydrogen ions into the glandular lumens where union with chloride ions forms hydrochloric acid
2) Chief cells secrete the proenzyme pepsinogen that in the acidic environment of the glandular lumens is converted to pepsin the active digestive enzyme

Question 6

Cite the function of intrinsic factor, a secretory product of the parietal cells.

Answer 6

1) Intrinsic factor is a glycoprotein that facilitates vitamin B12 (cobalamin) absorption in the proximal small intestine
2) Vitamin B12 is essential for production of erythrocytes in bone marrow and normal neurologic function

Question 7

Is the body or pylorus of the stomach depicted in this image?

Answer 7

Body of the stomach due to the presence of multiple cell types (Parietal, Chief, and Mucus cells)

Question 8

How does pernicious anemia affect the gastric mucosa?

Answer 8

Pernicious anemia—a form of megaloblastic anemia—is an autoimmune disease resulting in marked atrophy of gastric mucosa, destruction of parietal cells, and failure to produce intrinsic factor, which leads to vitamin B12 malabsorption

Question 9

What forms the muscularis externa of the stomach? What is mesothelium covering the thin adventitia also called?

Answer 9

1) Smooth muscle forms the muscularis externa of the stomach

2) Mesothelium covering the thin adventitia is the visceral peritoneum

Question 10

What does thickening of the circular layer of the muscularis externa create?

Answer 10

Thickening of the circular layer of the muscularis externa creates the pyloric sphincter

Question 11

Why is projectile vomiting a symptom of pyloric stenosis?

Answer 11

Pyloric stenosis is characterized by an extreme narrowing of the pyloric lumen, and the passage of food is obstructed, resulting in severe projectile vomiting