gastric secretion Flashcards
the following are gastic exocrine secrections with secreting cells respectively
- HCl - parietal
- pepsin - chief
- gastric lipase - chief
- intrinsic factor - parietal
- NaHCO3 - epithelial
- mucus
True or False. Gastric parietal cells undergo a morphological change when activated to secrete HCl, they have structures called TUBULOVESICLES.
False. CANALICULUS
what enzyme hydrolyzes CO2 to finally form a proton and bicarb?
CA ( carbonic anhydrase)
How are the protons transported out of the parietal cell?
H-K atpase pump
What make the stomach lumen favaroble for activity of Pepsin and lipases?
HCL. from the proton and cloride ions transported out of the parietel cell
Which inhibitor would be better to inhibit gastric secretions, omeprazole or cimetidine?
2nd generation inhibitor omeprazole
stops H-K-ATPase transporter on the lumen side of membrane
what part of the ENS (enteric “autonomic” nervous system for GI) innervates smooth muscle of GI tract?
Myenteric plexus (outer)
The submucosal plexus (inner plexus) is responsible for what?
innervates the mucosal lining of the tract
what type of nervce fibers enhance secretions and motility?
parasympathetic
What are the reflexes influencing HCl secrection into the lumen of the stomach
Stimulatory:
filling
peptides
vagus
inhibitory
pH < 3
What increase the HCl secrection from parietal cell?
ACh
histamine
gastrin
What decrease (inhibits) the HCl secrection from the parietel cell?
somatostatin
how does somatostatin work?
blocks gastrin release and inhibits ECL and parietel cells
what are the functions of HCl
digest PRO — protonate amino acids
activate pepsin
kill bacteria
True or false. the optimum pH for Pespin is 9.
False 3 inactive at pH 7
