GI secretions Flashcards
Where is gastrin produced?
G cells in stomach
What is the effect of gastrin?
Increases stomach motility, growth of gastric mucosa and acid production
What is gastrin stimulated by?
Stomach distension, amino acids, vagal
What is gastrin inhibited by?
Acidity, somatostatin, CCK, secretin
Where is CCK secreted from?
I cells in duodenum and jejunum
What is the action of CCK?
Contraction of gall bladder, pancreatic enzyme secretion, inhibits stomach acid
What is CCK stimulated by?
Fatty acids and amino acids
What is CCK inhibited by?
Trypsin and somatostatin
Where is secretin released from?
S cells in duodenum
What is the action of secretin?
HCO3- secretion from pancreas, inhibits bile secretion and stomach acid
What is secretin stimulated by?
Acidity, fatty acids
Where is somatostatin secreted from?
D cells in pancreatic islets and GI mucosa
What is the action of somatostatin?
Inhibits stomach acid, pancreatic (enzyme and HCO3-), pepsinogen, CCK, secretin, insulin and glucagon secretions.
What is somatostatin stimulated by?
Acidity
What is somatostatin inhibited by?
Vagal stimulation (ACh)
Where is vasoactive intestinal polypeptide (VIP) secreted from?
Parasympathetic ganglia in sphincters, gall bladder, SI
What is VIP’s action?
Increases intestinal motility and intestinal fluid secretion
What stimulates VIP?
Stomach distension, vagal stimulation
Where is motilin produced?
Small intestine M cells
What is the function of motilin?
Increases intestinal motility and migrating motor complexes
What stimulates motilin?
Fasting
Where is intrinsic factor secreted from?
Parietal cells of the stomach
What is the function of intrinsic factor?
Cobalamine (B12) uptake in the liver
What is secretin inhibited by?
Somatostatin
