Gastric Motility and Gastric Acid Production Flashcards
Where is the pyloric gland area?
antrum
Where is the oxyntic mucosa?
fundus and body
What is secreted from the oxyntic mucosa?
HCl, Pepsinogen, Intrinsic Factor, histamine, mucus
What is secreted from the pyloric gland area?
gastrin, somostatin and mucus
What does gastrin do?
stimulated HCl secretion
What does somastatin do?
inhibit HCl secretion
What does HCl do?
activates pepsinogen to pepsin
denatures protein
kills most microorganisms
What does pepsinogen do?
precursor for pepsin
What dodes intrinsic factordo?
bind B12 vitamin, allowing absorption in the terminal ileum
What does histamine do?
stimulate HCl secretion
What cell secretes HCl?
gastric parietal cell
What is HCl secretion in the gastric parietal cell controlled by?
D cells (somastatin) and G cells (gastrin) and histamine
Where is H+/K+ ATPase in the resting state of the parietal cell?
largely within tubulovesicles
Where is H+/K+ ATPase in the stimulated state?
the apical membrane, taking residence in extended microvilli
What are the 3 phases of gastric secretion?
cephalic, gastric and intestinal
Which stage of gastric secretion occurs before food reaches the stomach?
cephalic
Which stage of gastric secretion occurs after food leaves the stomach?
intestinal
In the cephalic stage, what happens to somatostatin?
decreases between D cell and G cell
What happens to ACh in the cephalic stage?
increases
What happens to GRP in the cephalic stage?
increases
What happens to histamine and gastrin in the cephalic stage?
increase
In what stage does distension occur via mechoceptors to G cells?
gastric
What are added to the G cells in the gastric stage?
protein digestion products
In which stage of secretion is acid secretion switched off?
intestinal
What do factors that reduce gatric motility also do?
reduce gastric secretion
What do prostaglandins do?
reduce acid secretion and increase mucus, bicarbonate secretion and blood flow
