GI 13a Flashcards
What are the four components of gastric secretions?
- Mucus
- HCl
- Enzymes
- Hormones
What does the Mucus gastric secretion do?
Lubricates and protects stomach lining
What does the HCl stomach secretion do?
- Solubilizes some food
- Kills ingested microbes
- Cleaves pepsinogen
What does the pepsinogen stomach secretion do?
Gets converted to Pepsin and cleaves proteins
Where do the hormones secreted by the stomach go?
Into the blood stream
What cleaves Pepsinogen?
HCl
What cells produce mucus in the stomach?
Surface mucous cells
Which cells in the stomach secrete HCl?
Parietal cells
What do ECL cells in the stomach secrete?
Histamines
What do chief cells in the stomach secrete?
Pepsinogen
What is HCl production mediated by?
Cephalic and Gastric Phase responses
What stimulates HCl production?
Gastrin, Histamine and ACh
What is HCl production inhibited by?
Somatostatin
How do the regulators of HCl production work?
They will either stimulate or inhibit the docking of a hydrogen potassium ATPase pump to the cell wall increasing or decreasing proton pumps activity
What are G-cells?
Enteroendocrine cells on the gastric epithelium
What stimulates G cells to secrete gastin?
Protein rich meals and amino acids
What does Gastrin released by G cells do?
Go into the circulation and influence ECL cells to increase histamine production and parietal cells to increase HCl
What does increased histamine release by ECL do?
Signals the parietals cells to increase acid production
What are the two main components of pancreatic secretions?
- Bicarbonate
* Enzymes
What is the function of the bicarbonate released by the pancreas?
To neutralize chyme
What are the exocrine cells of the pancreas?
Acinar cells
What are Acinar cells responsible for?
Production of pancreatic enzymes
What are duct cells in the pancreas responsible for?
Bicarbonate secretion
What does the pancreatic duct merge with?
The common bile duct
What does the Sphincter of Oddi control?
The release of bile and pancreatic juice into the SI
What increases secretin production from the SI?
High acidity
What does SEcretin do?
Causes the pancreas to increase bicarbonate secretion
What causes increased CKK secretion?
High protein meals
How does increased CCK affect the pancreas?
It causes the pancreas to produce more enzymes
