Stomach pylorus, histology, discussion, viva, oral, questions

1. What are the four main layers of stomach pylorus?
• From within (lumen) outwards
• Mucosa (mucous membrane)
• Submucosa
• Muscularis externa
• Serosa
2. What are the layers of mucosa?
• From lumen outwards
• Epithelial lining
• Lamina propria
• Muscularis mucosae
3. What is the epithelial lining in stomach pylorus?
• Simple columnar epithelium
4. What are gastric pits?
• Gastric pits are the invaginations of surface epithelium into the lamina propria and gastric glands open into it. It is more than 1/2 the thickness of the mucosa
5. What are the components of lamina propria?
• Loose connective tissue
• Blood vessels
• Lymphatics
• Lymphocytes
• Nerves
• Pyloric glands
6. What are pyloric glands?
• They are branched and highly coiled tubular glands extending the whole thickness of lamina propria and open into gastric pits
7. Name the different types of cells in pyloric glands.
• Mucous cells
• Argentaffin cells or enteroendocrine cells
8. What is muscularis mucosae?
• Muscularis mucosae is a thin layer of smooth muscle arranged as inner circular and outer longitudinal layers around the lamina propria
9. What are the components of submucosa?
• Dense connective tissue
• Larger blood vessels
• Submucosal (Meissner's) plexus of autonomic nerves
10. What are the components of muscularis externa?
• Inner oblique smooth muscle layer
• Middle circular smooth muscle layer
• Outer longitudinal smooth muscle layer
• Between outer two layers is thin connective tissue layer with blood vessels, lymph vessels, myenteric (Auerbach's) plexus of autonomic nerves
11. What is serosa?
• Serosa- thin layer of loose connective tissue with numerous blood vessels, lymphatics, adipose tissue covered by simple squamous epithelium (mesothelium)
12. Difference between serosa and adventitia

Serosa	Adventitia
Thin layer of loose connective tissue with numerous blood vessels, lymphatics, adipose tissue covered by mesothelium (simple squamous epithelium)	Loose connective tissue with numerous blood vessels, lymphatics, adipose tissue which merges with surrounding tissues. Mesothelium is absent

13. What is mesothelium?

• It is a simple squamous epithelium covering a thin layer of loose connective tissue in the abdomen surrounding the viscera

14. What is the function of Meissner's plexus?

• Meissner’s plexus regulates the configuration of the luminal surface, controls glandular secretions, alters electrolyte and water transport and regulates local blood flow

15. What is the function of Myenteric plexus?

• Myenteric plexus supplies the GIT and controls the gastric motility

16. Give the differences between the stomach fundus and pylorus

	Fundus	Pylorus
Mucosa	Thrown into temporary folds called rugae in empty stomach, disappears when distended	-
Gastric pits	1/4th of thickness of mucosa	More than ½ the thickness of mucosa
Gastric glands	Long simple tubular glands	Branched or coiled tubular glands
Cells	Mucus neck cells, Parietal cells, chief cells, argentaffin cells	Mucus cells, argentaffin cells
The rest of the structure is same in both