Chapter 28: GI Hormones

Question 1

Produced by G cells in stomach antrum

Answer 1

Gastrin

Question 2

What stimulates secretion of gastrin?

Answer 2

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

Question 3

What inhibits secretion of gastrin?

Answer 3

Inhibited by pH

Question 4

Gastrin target cells

Answer 4

Parietal cells and chief cells

Question 5

Gastrin elicited response

Answer 5

Increased HCl, intrinsic factor, and pepsinogen secretion

Question 6

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

Answer 6

Omeprazole

Question 7

Mainly produced by D cells in stomach antrum

Answer 7

Somatostatin

Question 8

What stimulates secretion of somatostatin?

Answer 8

Secretion stimulated by acid in duodenum

Question 9

Somatostatin target cells

Answer 9

Many, is the great inhibitor

Question 10

Somatostatin elicited response

Answer 10

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

Question 11

Can be used to decreased pancreatic fistula output

Answer 11

Octreotide (somatostain analogue)

Question 12

Produced by I cells of duodenum

Answer 12

CCK

Question 13

What stimulates secretion of CCK?

Answer 13

Amino acids and fatty acid chains

Question 14

CCK elicited response

Answer 14

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

Question 15

Produced by S cells of duodenum

Answer 15

Secretin

Question 16

What stimulates secretin secretion?

Answer 16

Stimulated by fat, bill, pH

Question 17

What inhibits secretin secretion?

Answer 17

Inhibited by pH > 4.0, gastrin

Question 18

Secretin elicited response

Answer 18

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-)

Question 19

Produced by cells in gut and pancreas

Answer 19

Vasoactive intestinal peptide

Question 20

What stimulates secretion of vasoactive intestinal peptide?

Answer 20

Secretion stimulated by fat, acetylcholine

Question 21

Vasoactive intestinal peptide elicited response

Answer 21

Increased intestinal secretion (water and electrolytes) and motlity

Question 22

Mainly released by alpha cells of pancreas

Answer 22

Glucagon

Question 23

What stimulates secretion of glucagon?

Answer 23

Decreased glucose, increased amino acids, acetylcholine

Question 24

What inhibits secretion of glucagon?

Answer 24

Inhibited by increased glucose, increased insulin, somatostatin

Question 25

Glucagon elicited response

Answer 25

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

Question 26

Released by beta cells of the pancreas

Answer 26

Insulin

Question 27

What stimulated secretion of insulin?

Answer 27

Glucose, glucagons, CCK

Question 28

What inhibits secretion of insulin?

Answer 28

Somatostatin

Question 29

Insulin elicited response

Answer 29

Cellular glucose uptake, promotes protein synthesis

Question 30

Secreted by islet cells in pancreas

Answer 30

Pancreatic polypeptide

Question 31

What stimulates secretion of pancreatic polypeptide?

Answer 31

Food, vagal stimulation, other GI hormones

Question 32

Pancreatic polypeptide elicited response

Answer 32

Decreased pancreatic and gallbladder secretion

Question 33

Released by intestinal cells of gut

Answer 33

Motilin

Question 34

What stimulates release of Motilin?

Answer 34

Duodenal acid, food, vagus input

Question 35

What inhibits release of motion?

Answer 35

Somatostatin, secretin, pancreatic polypeptide, duodenal fat

Question 36

Motilin elicited response

Answer 36

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

Question 37

Where does erythromycin act to increase peristalsis?

Answer 37

Motilin receptor

Question 38

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

Answer 38

Bombesin (gastrin-releasing peptide)

Question 39

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

Answer 39

Peptide YY

Question 40

What mediates anorexia?

Answer 40

Hypothalamus

Question 41

Small bowel recovery

Answer 41

48 hours

Question 42

Stomach recovery

Answer 42

48 hours

Question 43

Large bowel recovery

Answer 43

3-5 days