Lecture 1-Hormones Of The GI Tract Table

Question 1

Gastrin-Site of secretion?

Answer 1

G cells of stomach

Question 2

Gastrin-Stimuli of secretion?

Answer 2

• Small peptides and amino acids
• Distention of stomach
• Vagal stimulation (via GRP)

Question 3

Gastrin-actions?

Answer 3

• Increase circulating levels of gastrin
• Increase acid (HCl) secretion by parietal cells
• Hypertrophy of gastric mucosa (increases # of parietal cells)

Question 4

Excess gastrin can cause?

Answer 4

Duodenal ulcers and steatorrhea

Question 5

How does excess gastrin cause steatorrhea?

Answer 5

Excess gastrin leads to excess acid which impairs pancreatic enzymes some of which are responsible for breaking down fat
-fat in feces

Question 6

CCK-hormone family?

Answer 6

Gastrin-CCK family

Question 7

CCK-Site of secretion?

Answer 7

I cells of the jejunum and duodenum

Question 8

CCK actions (2 main actions)?

Answer 8

• Increase pancreatic enzyme secretion
• Stimulates contraction of the gall bladder and relaxation of the sphincter of Oddi-gall bladder releases bile into duodenum

Question 9

CCK other actions?

Answer 9

• Increase pancreatic bicarb secretion (not a direct effect, it potentiates the effects of secretin)
• Stimulates growth of the exocrine pancreas and gall bladder
• Inhibits gastric emptying
• Can also act as a paracrine signal

Question 9

CCK inhibits gastric emptying

Answer 9

Allows fat and protein to sit in the stomach and digest since they need more time to digest than carbs

Question 10

Specific receptor for CCK?

-Non specific receptor for CCK? What other hormone uses this receptor?

Answer 10

CCK-specific receptor-CCK1/alpha

CCK/gastrin-receptor-CCKbeta

Question 11

CCK-stimuli of secretion?

Answer 11

• Small peptides and amino acids

- Fatty acids

Question 12

Secretin-hormone family?

Answer 12

Secretin-glucagon family

Question 13

Secretin-site of secretion?

Answer 13

S cells of duodenum

Question 14

Secretin-stimuli of secretion?

Answer 14

• Acid (H+) in the duodenum

- Fatty acids in the duodenum

Question 15

Secretin-similar to what other hormone?

Answer 15

Glucagon

Question 16

Secretin-actions?

Answer 16

• Increase pancreatic and biliary bicarb secretion
• Decrease gastric H secretion
• Inhibits trophic effect of gastrin on gastric mucosa
• Can also act as a paracrine signal

Question 17

GIP-two names?

Answer 17

Glucose-dependent insulinotropic peptide and gastric inhibitory peptide

Question 18

Gastrin-hormone family?

Answer 18

Gastrin-CCK family

Question 19

GIP-hormone family?

Answer 19

Secretin-glucagon family

Question 20

GIP-site of secretion?

Answer 20

Duodenum and jejunum

Question 21

GIP-stimuli of secretion?

Answer 21

• Fatty acids
• Amino acids
• Oral glucose

Question 22

GIP actions?

Answer 22

• Increase insulin secretion from pancreatic beta cells

- Decrease gastric H secretion

Question 23

What would be more effective in increasing insulin secretion-oral or intravenous glucose administration and why?

Answer 23

Oral glucose administration would be more effective because it would stimulate GIP which stimulates insulin secretion and has direct stimulatory effects on beta cells

Question 24

Paracrine regulators?

Answer 24

Somatostatin and histamine

Question 25

Somastatin-Secreted by?

Answer 25

- D cells of the GI mucosa | - Also secreted outside of the GI tract in the hypothalamus and delta cells of the exocrine pancreas

Question 26

Somatostatin-stimulus?

Answer 26

Low luminal pH (acidic)

Question 27

Somatostatin-actions?

Answer 27

- Inhibits gastric H secretion | - Inhibits secretion of other GI hormones including histamine

Question 28

Histamine-Where is it stored and secreted from in the stomach?

Answer 28

Stored and secreted from enterochromaffin-like (ECL) cells in gastric glands

Question 29

Histamine-target what specific type of cell?

Answer 29

Parietal cells

Question 30

Histamine-action?

Answer 30

Stimulate acid production

Question 31

Histamine-inhibited by?

Answer 31

Somatostatin

Question 32

Zollinger-Ellison syndrome

Answer 32

Gastrin-secreting tumors