Physiology: gastric secretions Flashcards
What are the 2 types of glands in the stomach?
Gastric (oxyntic) glands
Pyloric glands
What does oxyntic mean?
Acid producing
Within the stomach, where are gastric and pyloric glands made?
Gastric glands: proximal 80% of the stomach
Pyloric glands: distal 20% of the stomach (near the pyloric sphincter)
What cell types do gastric glands have? Pyloric glands?
Gastric:
- Parietal cells
- Chief cells
- Enteroendocrine cells
- Mucus cells
Pyloric
- Chief cells
- Enteroendocrine cells
- Mucus cells
What is secreted by:
- Mucus cells
- Chief cells
- Parietal cells?
Mucus cells: mucus and bicarbonate (buffer)
Chief cells: secrete pepsinogen
Parietal cells: secrete HCl (gastric acid) and intrinsic factor (enables B12 absorption in ileum)
Enteroendocrine cells:
- Which subtypes are found in gastric glands? What do they secrete?Gast
- Which ones are found on pyloric glands?
Gastric glands:
- G cells: secrete gastrin
- D cells: secrete somatostatin
Pyloric glands:
- G cells and D cells
- Enterochromaffin like cells: secrete histamine
Gastric glands: label the cell types
(It’s ok if you mix up the green)
Parietal cells
- Are they pumping H+ into the stomach against a large concentration gradient?
- Diagram of the molecular processes involving HCl secretion?
- What is the name of the pump that pumps H+ into the lumen?
- During heavy acid secretion, what happens to blood coming from the stomach?
Yes
H+/K+ ATPase
Blood coming from stomach has high HCO3- content (as it’s made when HCl is made)
What 4 neurohormonal acts regulate acid secretion in parietal cells? Acronym?
What are 2 of the secondary messengers involved in inserting more H+/K+ ATPase pumps into the apical membrane, in response to these factors?
HAGS - histamine, Ach, gastrin, somatostatin
cAMP, PKA
What effect does (gastric) acid secretion have upon pepsinogen?
It activates pepsinogen to form pepsin.
Pepsin helps digest proteins - specifically the collagen in meat
