GI Function

Question 1

What does gastrin do?

Answer 1

increases acid secretion, gastric mucosa growth, and gastric motility

Receptor: CCK-B

Question 2

What does CCK do?

Answer 2

contracts gall bladder
relaxes sphincter of Oddi
stimulates enzyme secretion from pancreas

*important for getting bile out to solubilize fat

Question 3

What does secretin do?

Answer 3

In duodenum and jejuneum:
promotes secretion of bicarb from pancreas and bile secretion (neutralizes stomach acid to prodect pancreatic lipases from being denatured in acid)

Question 4

What do incretins do?

Answer 4

Intestine:
augment insulin release from pancreatic Beta cells, BUT ONLY IN RESPONSE TO GLUCOSE

Include: GIP (duodenum) and GLP1 (illeum and cecum)

Question 5

GI control of food intake:

What stimulates positive hypothalamic input?

Answer 5

appetizing sight/smell/taste of food signals from cerebral cortex

GHRELIN from an empty stomach

Question 6

GI control of food intake:

What stimulates negative hypothalamic input?

Answer 6

1) afferents from stomach relaying fullness
2) GI hormones: Insulin, PYY, CCK
3) adipose tissue: leptin