Chapter 28: GI Hormones Flashcards Preview

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Flashcards in Chapter 28: GI Hormones Deck (43):
1

Produced by G cells in stomach antrum

Gastrin

2

What stimulates secretion of gastrin?

Amino acids, vagal input (acetylcholine), calcium ETOH, antral distention, pH > 3.0

3

What inhibits secretion of gastrin?

Inhibited by pH

4

Gastrin target cells

Parietal cells and chief cells

5

Gastrin elicited response

Increased HCl, intrinsic factor, and pepsinogen secretion

6

Blocks H/K ATPase of parietal cell (final pathway for H+ release)

Omeprazole

7

Mainly produced by D cells in stomach antrum

Somatostatin

8

What stimulates secretion of somatostatin?

Secretion stimulated by acid in duodenum

9

Somatostatin target cells

Many, is the great inhibitor

10

Somatostatin elicited response

Inhibits gastrin and HCl release, inhibits release of insulin, glucagon, secretin, and motion; decreased pancreatic and biliary output

11

Can be used to decreased pancreatic fistula output

Octreotide (somatostain analogue)

12

Produced by I cells of duodenum

CCK

13

What stimulates secretion of CCK?

Amino acids and fatty acid chains

14

CCK elicited response

Gallbladder contraction, relaxation of sphincter of Oddi, increased pancreatic enzyme secreiton

15

Produced by S cells of duodenum

Secretin

16

What stimulates secretin secretion?

Stimulated by fat, bill, pH

17

What inhibits secretin secretion?

Inhibited by pH > 4.0, gastrin

18

Secretin elicited response

Increased pancreatic HCO3- release, inhibits gastrin release (this is reversed in patients with gastrinoma), and inhibits HCl release
- High pancreatic duct output: increased HCO3-, decreased Cl-
- Slow pancreatic duct output: increased Cl-, decreased HCO3- (carbonic anhydrase in duct exchanges HCO3- for Cl-)

19

Produced by cells in gut and pancreas

Vasoactive intestinal peptide

20

What stimulates secretion of vasoactive intestinal peptide?

Secretion stimulated by fat, acetylcholine

21

Vasoactive intestinal peptide elicited response

Increased intestinal secretion (water and electrolytes) and motlity

22

Mainly released by alpha cells of pancreas

Glucagon

23

What stimulates secretion of glucagon?

Decreased glucose, increased amino acids, acetylcholine

24

What inhibits secretion of glucagon?

Inhibited by increased glucose, increased insulin, somatostatin

25

Glucagon elicited response

Glycogenolysis, gluconeogensis, lipolysis, ketogenesis, decreased gastric acid secretion, decreased gastrointestinal motility, relaxes sphincter of Oddi

26

Released by beta cells of the pancreas

Insulin

27

What stimulated secretion of insulin?

Glucose, glucagons, CCK

28

What inhibits secretion of insulin?

Somatostatin

29

Insulin elicited response

Cellular glucose uptake, promotes protein synthesis

30

Secreted by islet cells in pancreas

Pancreatic polypeptide

31

What stimulates secretion of pancreatic polypeptide?

Food, vagal stimulation, other GI hormones

32

Pancreatic polypeptide elicited response

Decreased pancreatic and gallbladder secretion

33

Released by intestinal cells of gut

Motilin

34

What stimulates release of Motilin?

Duodenal acid, food, vagus input

35

What inhibits release of motion?

Somatostatin, secretin, pancreatic polypeptide, duodenal fat

36

Motilin elicited response

Increased intestinal motility (small bowel; phase III peristalsis) -> erythromycin acts on this receptor

37

Where does erythromycin act to increase peristalsis?

Motilin receptor

38

Increase intestinal motor activity, increase pancreatic enzyme secretion, increase gastric acid secretion

Bombesin (gastrin-releasing peptide)

39

Released from terminal ileum following a fatty meal -> inhibits acid secretion and stomach contraction; inhibits gallbladder contraction and pancreatic secretion

Peptide YY

40

What mediates anorexia?

Hypothalamus

41

Small bowel recovery

48 hours

42

Stomach recovery

48 hours

43

Large bowel recovery

3-5 days