hormonal control of GI

what do parietal cells in the stomach secrete?

HCl

what do chief cells in the stomach secrete?

pepsinogen (converted to pepsin in low pH enviros)

what do G cells in the stomach secrete?

gastrin

what is gastrin secretion stimulated by?

• pH increase

• stretching of stomach walls

• food in the stomach

what’s the function of gastrin?

regulate pH of the stomach

what does gastrin do to regulate the pH of the stomach?

binds to parietal cells, which then secrete HC

what is secretin secretion stimulated by?

low pH and precense of carbs in the duodenum

what’s the fxn of secretin?

regulate digestion in the duodenum

what does secretin do to regulate digestion in the duodenum?

creates bicarbonate to raise pH in duodenum to a more neutral level

what is secretin secreted by?

S cells of duodenum

what is CCK secretion stimulated by?

low pH and presence of fats and protein in the duodenum

what’s the function of CCK?

inhibit smooth muscle contraction of the stomach

how does CCK inhibit smooth muscle contraction of the stomach?

slowing process of food moving into the duodenum, so the small intestine has more time to absorb nutrients

what cells secrete CCK?

i cells of duodenum