| Question |
Answer |
| What phase is regulated by gastrin and histamine? |
Gastric phase |
| Where does the gastrin bind? |
Gastric receptors on parietal cells |
| What does gastrin cause? |
activates proton pump |
| What does histamine cause? |
paracrine secretion (regulated by gastrin) turns on proton pump |
| When does the gastric phase occur? |
when food enters the stomach |
| What happens to gastrin in the intestinal phase? |
decreases - secretin provides negative feedback for gastrin |
| What phase does the majority of acid output occur? |
gastric phase |
| Where does secretin come from? |
duodenum |
| What stimulates secretin release? |
acid production |
| What innervates cephalic phase? |
vagal innervation |
| What do tums do? |
decrease pH by neutralizing acid in stomach - bicarb - immediate relief, titrates acid |
| What does tagamet do? |
hits the histamine receptors, decreases HCl production |
| What do nexium and prilosec do? |
knocks off the proton pump - stops acid production |
| What is the drug of choice for excess acid production in stomach? |
nexium or prilosec |
| What are the consequences of nexium or prilosec? |
loses protective function of acid against bacteria, cuts off negative feedback loop and increases gastrin levels, interferes with secretin |
| What shuts off gastrin secretion? |
pH drops back down, around 2 |
| What causes ulcers? |
H. pylori |
| What do NSAIDS cause in the stomach? |
shut off mucous barrier |
| What is the treatment for ulcers? |
antibiotic, but it's hard to get it to the right spot |
| What is the name of the cell that secretes gastrin? |
G cell |
| What is the G cell sensitive to? |
amino acids in the lumen |
| Is gastrin a hormone? |
yes |
| What does somatostatin do to gastrin? |
inhibits - paracrine |
| What effect does high H+ cause on somatostatin? |
cause secretion of somatostatin |
| How does secretin work? |
acts as a hormone - inhibits gastrin |
| Where is somatostatin secreted? |
antrum of the stomach |
| Where are the G-cells located? |
antrum |
| Where does the secretin come from? |
duodenum |
| What other use does nexium have? |
acid reflux |
| Why would acid be damaging to the esophagus? |
esophagus does not have protective mucus - constant acid wears it down |
| Can you have hyperosmotic materials in the stomach? |
Yes - stomach wall does not absorb water |
| What 2 other things can turn on acid production? |
alcohol and caffeine |
| Does the chyme enter the small intestine? |
NO - small intestine is very sensitive to acid |
| What does the duodenum do to neutralize the acidic chyme? |
secretes bicarbonate |
| Why does the chyme take so long to go from stomach to duodenum |
it has to be neutralized - goes slowly |
| What role does secretin have in neutralization of acidic chyme in the duodenum? |
signals pancreatic ducts to secrete bicarbonate |
| Where is bicarb secreted from to the duodenum? |
pancreas |
| What does CHO trigger in the duodenum? |
GLP-1 (glycogen-like peptide 1) |
| Where does GLP-1 act? |
pancreas -islet |
| What does GLP-1 signal to the islet cells produce? |
insulin |
| What do fats and peptides trigger in duodenum? |
CCK -colecystekinin (check spelling) |
| What does CCK signal? |
secretion of zyomgens (enzymes) from the pancreas |
| What do zymogens do? |
degrade |
| What is the other target site of the CCK besides the pancreas? |
gall bladder |
| What does the CCK signaling of the gall bladder cause? |
secretion of bile |
| Where is the acinus located? |
pancreas |
| What does the acinus hold? |
zymogens (inactive until released into duodenum) |
| What do duct cells in the pancrease secrete? |
HCO3 |
| What effect would damage to the pancreas cause? |
potential activation of zymogens in wrong place |
| What signals duct cells to release HCO3? |
secretin |
HHS Shrek
