GI Substances Flashcards
What is the source of CCK?
I cells of duodenum and jejunum
What are the functions of CCK?
Increase stomach distensibility and dec emptying
Contract gallbladder and relax sphincter of oddi
Increase pancreatic secretions
When is CCK released? Think enterogastric reflex?
CCK is released due to fats being present in duodenum
What is the source of gastrin?
G cells of antrum
What are the functions of gastrin?
Increase H secretion
Stimulate mucosa growth
Stimulate gastric contractions
When is gastrin released?
What inhibits gastrin?
Gastrin is released due to stomach distention, arlkalinization, AA, peptides, or vagal stimulation
Gastrin is inhibited by very low pH
What is the source of GIP?
GIP is released from K cells of duodenum and jejunum
What are the functions of GIP?
GIP decreases H secretion and decreased gastric motility
What is the source of motilin?
Motilin is released from small intestines
What are the functions of motilin?
Motilin increases gastric motility Mediates MMC (clear stomach during fasting periods)
What is the source of secretin?
S cells of duodenum
What are the functions of secretin?
Inhibit gastrin to decrease gastric acid secretion (enterogastric)
Decrease small intestine contractions
Increase HCO3 secretion and bile secretion
What is the source of somatostatin?
D cells
What are the functions of somatostatin?
Decrease gastric acid, pepsinogen, insulin, and glucagon release
Inhibit gallbladder contractions and pancreatic secretions
What is the source of VIP?
Parasympathetic ganglion
