Gastric Secretion Flashcards
Main fx of fundus?
Storage
Main fx of body?
Storage
Mucus, HCl, Pepsinogen, Intrinsic factor
Main fx of Antrum
Mixing,
Gastrin
What do mucous neck cells prod?
Mucous
What do chief cells prod?
Pepsinogen
What do parietal cells prod?
HCL and intrinsic factor
What is the emzyme in parietal cells that catalyses the reaction of h2o and co2 to form h2co3?
Carbonic Anhydrase
how is HCL increased in secretion?
4 ways
Acetylcholine (m3 muscuranic) Gastrin -> inc Ca rise in cell -> stims protein kinases -> increases K/H
HIstamine (G stimulatroy)
Stims G protein -> a cyclase converts ATP to cAMP
-> protein kinase
Prostaglands (G-inhibitory)
What is an ECL cell?
Enterochromaffin-like cell
What is the cephalic phase of gastric acid secretion?
Stim before swallowing
Vagus nerve and Gastric/ACh
What is the Gastric phase?
Phase in which stomach is relaxed.
Stomach distends stims vagus
Peptides in lumen stim G cells to secrete gastrin
gastrin stims ECL to release histamine
What inhibits gastrin?
Gastric Phase - Dec pH
Intestinal Phase -
Acid in DD -> splachnic reflex -> Decr gastrin secr an stim of parietal cells
Fat in DD -> GIP release
What hormones are released from DD mucosa?
secretin, CCK, GIP
What causes the release of DD hormones?
to acid, hypertonic solutions, fatty acids or monoglycerides in duodenum
What are the main 2 fx of DD hormones?
Decr Gastric emptying
Decr Gastric Acid Secretion
What is pepsingoen?
a zymogen - innactive enzyme
What happens to pepsinogen when the pH decreases?
The ogen part is dropped off allowing free pepsin to do it’s fx
What is the role of gastric mucous?
Prod bt epi cells and mucus neck cells Pepsin = denatured at ph7 Cytoprotective role Prevents pepsin degredation and acid burn allows for hco3 to have neutal secretion
Where is B12complex absorped?
ileum
