GI hormones

Question 1

What cell type secretes gastrin?

Answer 1

G cells

Question 2

Where are G cells located?

Answer 2

Antrum

Duodenum

Question 3

What factors increase gastrin secretion?

Answer 3

Amino acids

Peptides

Gastric distension

Increased pH

Parasympathetic (using GRP)

Question 4

What receptors does Gastrin act at?

Answer 4

CCK2 receptor called CCK-B

Question 5

How does gastrin affect the stomach?

Answer 5

Parietal cells: inc. HCl, IF secretion

Chief cells: inc. pepsinogen, gastric lipase

Mucosal cells: inc. # and size

ECL cells: inc. histamine release

Question 6

What cells secrete histamine?

Answer 6

ECL

Mast cells

Question 7

Where are ECL and mast cells located?

Answer 7

Gastric glands

GI mucosa

Question 8

What factors increase secretion of histamine?

Answer 8

Gastrin

Parasympathetic

Gastric distension

Question 9

What receptor does histamine act on?

Answer 9

H2

Question 10

What affect does histamine have on the stomach?

Answer 10

Parietal cells: increase HCl, IF

Chief cells: increase pepsinogen, gastric lipase

Question 11

How is carbonic acid distributed from the parietal cell?

Answer 11

acid is pumped out to lumen

Bicarbonate is pumped out to blood on basolateral end of cell

Question 12

How is H+ pumped out of parietal cell?

Answer 12

H,K - ATPase: recycles potassium to pump out acid

Question 13

What cells secrete cholecystokinin?

Answer 13

I cells

Question 14

Where are I cells located?

Answer 14

Duodenum

Jejunum

Question 15

What factors increase secretion of CCK?

Answer 15

From CCK releasing peptide:
Fatty acids
Amino acids
Peptides

Monitor Peptide

Question 16

What receptor does CCK act at?

Answer 16

CCK1 receptor called CCK-A

Question 17

Where do CCK’s actions have effect?

Answer 17

Pancreas

Gallbladder

Sphincter of Oddi

Gastric emptying

CNS

Question 18

What effect does CCK have?

Answer 18

Pancreas:
Acinar cells = inc. enzyme release
Ductal cells = potential HCO3 secretion by secretin

Gallbladder = contraction

Sphincter of Oddi = relaxation (via NO)

Gastric emptying = slowed

CNS = increases feeling of fullness

Question 19

What cells secrete Secretin?

Answer 19

S cells

Question 20

Where are S cells located?

Answer 20

Duodenum

Jejunum

Question 21

What factors increase secretion of secretin?

Answer 21

Low pH

Fatty acids

Question 22

What receptor does secretin act on?

Answer 22

SCTR

Question 23

Where does secretin’s actions have effect?

Answer 23

Pancreas

Bile duct

G cells

Gastric emptying

Question 24

What effect does Secretin have?

Answer 24

Pancreas
Ductal cells = inc. HCO3 secretion
Acinar cells = potentials enzyme release by CCK

Bile duct = inc. HCO3 secretion

G cells = dec. gastrin release

Gastric emptying = slowed

Question 25

What cells secrete Somatostatin?

Answer 25

D cells

Question 26

Where are D cells located?

Answer 26

Stomach Small intestines Pancreas

Question 27

What factors increase SST secretion?

Answer 27

Low pH Fatty acids Amino acids Peptides

Question 28

What receptor does SST act on?

Answer 28

SSTR

Question 29

Where do SST's actions have an effect?

Answer 29

Stomach Duodenum Pancreas Gallbladder

Question 30

What effects does SST have?

Answer 30

Stomach: G cells = dec. gastrin release Parietal cells = dec. HCl, IF Chief cells = dec. pepsinogen, gastric lipase Duodenum I cells: decrease CCK release Pancreas Acinar cells: dec. enzyme Beta cells = dec. insulin release Alpha cells = dec. glucagon release Gallbladder = dec. contraction (mostly from dec. CCK around)

Question 31

What cells secrete glucose-dependent insulinotropic peptide?

Answer 31

K cells

Question 32

Where are K cells located?

Answer 32

Duodenum Jejunum

Question 33

What factors increase GIP secretion?

Answer 33

Glucose Fatty acids

Question 34

What receptor does GIP act on?

Answer 34

GIP receptor

Question 35

What actions does GIP have?

Answer 35

Pancreas Beta cells: inc. insulin release Gastric emptying: slowed

Question 36

What cells secrete motilin?

Answer 36

M cells

Question 37

Where are M cells located?

Answer 37

Duodenum Jejunum

Question 38

What factors increase motilin secretion?

Answer 38

Fasting

Question 39

What receptor does motilin act on?

Answer 39

Motilin receptor

Question 40

What actions does Motilin have?

Answer 40

Migrating motor complex (MMC): Peristaltic sweep Relaxes pyloric sphincter

Question 41

What does intrinsic factors help with?

Answer 41

Vitamin B12 absorption

Question 42

What effects do vagal stimulation have on GI hormones?

Answer 42

Chief cells: inc. gastric lipase, pepsinogen Parietal cells: inc. HCl, IF ECL cells: inc. histamine G cells: inc. gastrin

Question 43

What effect does prostaglandin stimulation have on GI hormones?

Answer 43

Surface mucous cells: inc. HCO3, mucus, trefoil peptides Chief cells: dec. gastric lipase, pepsinogen Parietal cells: dec HCl, IF

Question 44

What cells secrete bicarbonate?

Answer 44

Pancreatic duct cells Parietal cells