Diegestive System II Flashcards
Function of the mucus surface cells
- Physical barrier between the lumen and the epithelium
What stimulates the mucus surface layer?
- Tonic secret tonic secretion when the mucosa is irritated
Mucous neck layer secretion and function
- Secrete bicarbonate which acts as a buffer to the gastric acid to prevent damage to the epithelium
What stimulates the release of bicarbonate from mucous cells?
- Both the mucous and bicarbonate at decreased together
The function of parietal cells secreting gastric acid?
- Activation of pepsin which kills bacteria
Function of parietal cells secreting intrinsic factors
- Complexes with vitamin B12 to permit absorption
What stimulates the release of gastric acid and intrinsic factors?
- Gastrin, acetylcholine and histamines
What does the mucous neck and surface layer do for protection
- They protect the epithelial surface
- The NSAIDS and alcohol destroy the mucosal barrier which leads to gastric irritation
Function of the secretaries of histamines from Enterochroffmaffin like cells
- Stimulates gastric acid secretion
What stimulates the release of histamine?
Acetylcholine and gastrin
Function of chief cells secreting pepsin
- For the digestion of proteins
Function of chief cells secreting gastric lipase
- Initiates the digestion of fats
What stimulates the release of pepsin and gastric lipase
- Acetylcholine for acid secretion
Process of protein breakdown in the stomach
- Proteins initially breakdown in the stomach into pepsinogens
-This causes the inactive enzyme to be secreted from chief cells - The gastric acid then activates the inactive pepsin which digests the collagen in the meat
Fat breakdown in the stomach
- Triglycerides are broken down by gastric lipase which is secreted by the chief cells
- This forms diglycerides and a free fatty acid