PHGY 210 Lecture Notes - Trypsin Inhibitor, Amylase, Pancreatic Juice
Document Summary
Weak barrier (agents responsible: aspirin and nsaids, heliobacter pylori: normal barrier. Excessive hcl output (eg: gastrin producing factors) Also results in afferent fibres going up and efferent fibres as well. Gastrin is released in response to: secretagogues (products of protein digestion) (antrum lumen, local enteric reflexes, vagally-mediated reflexes. Physiological role of gastrin: hcl secretion, trophic effect. Histamine administration elicits large volume of gastric juice with lots of hcl. Histamine is constantly released and presented to the parietal cells as a tonic background, sensitizing them to other stimuli. Blocking this tonic background by h2-antagonists, inhibits acid secretion in response to ach and gastrin. (h+/k+ atpase, eg: nexium) H2 blockers are widely used to decrease hcl secretion (eg: pepsid). Optimal secretory activity is the result of an interplay between neural and hormonal mechanisms. Gastric secretion at any moment in time reflects a balance between stimulatory and inhibitory influences.