Gastrointestinal regulatory substances Flashcards Preview

Step 1 > Gastrointestinal regulatory substances > Flashcards

Flashcards in Gastrointestinal regulatory substances Deck (36):
1

Source of gastrin

G cells (antrum of stomach, duodenum)

2

Action of gastrin

- ↑ gastric H+ secretion
- ↑ growth of gastric mucosa
- ↑ gastric motility

3

Regulation of gastrin

- ↑ by stomach distention/ alkalinization, amino acids, peptides, vagal stimulation via gastrin releasing peptide (GRP)
- ↓ by pH

4

Source of somatostatin

D cells (pancreatic islets, GI mucosa)

5

Action of somatostatin

- ↓ gastric and pepsinogen secretion
- ↓ pancreatic and small intestine fluid secretion
- ↓ gallbladder contraction
- ↓ insulin and glucagon release

6

Regulation of somatostatin

- ↑ by acid
- ↓ by vagal stimulation

7

Source of cholecystokinin

I cell (duodenum, jejunum)

8

Action of cholecystokinin

- ↑ pancreatic secretion
- ↑ gallbladder contraction
- ↓ gastric emptying
- ↑ sphincter of Oddi relaxation

9

Regulation of cholecystokinin

↑ by fatty acids and amino acids

10

Source of secretin

S cells (duodenum)

11

Action of secretin

- ↑ pancreatic HCO3- secretion
- ↓ gastric acid secretion
- ↑ bile secretion

12

Regulation of secretin

↑ by acid, fatty acids in lumen of duodenum

13

Sources of glucose-dependent insulinotropic peptide

K cells (duodenum, jejunum)

14

Action of glucose-dependent insulinotropic peptide

- Exocrine: ↓ gastric H+ secretion
- Endocrine: ↑ insulin release

15

Regulation of glucose-dependent insulinotropic peptide

↑ by fatty acids, amino acids and oral glucose

16

Source of motilin

Small intestine

17

Action of motilin

Produces migrating motor complexes (MMCs)

18

Regulation of motilin

↑ in fasting state

19

Sources of vasoactive intestinal peptide

Parasympathetic ganglia in sphincters, gallbladder, and small intestine

20

Action of vasoactive intestinal peptide

- ↑ intestinal water and electrolyte secretion
- ↑ relaxation of intestinal smooth muscle and sphincters

21

Regulation of vasoactive intestinal peptide

- ↑ by distention and vagal stimulation
- ↓ by adrenergic input

22

Action of nitric oxide

↑ smooth muscle relaxation, including lower esophageal sphincter (LES)

23

Source of ghrelin

Stomach

24

Action of ghrelin

↑ appetite

25

Regulation of ghrelin

- ↑ in fasting state
- ↓ by food

26

Source of intrinsic factor

Parietal cells (stomach)

27

Action of intrinsic factor

Vitamin B12 binding protein required for B12 uptake in the terminal ileum

28

Source of gastric acid

Parietal cells (stomach)

29

Action of gastric acid

↓ stomach pH

30

Regulation of gastric acid

- ↑ by histamine, ACh, gastrin
- ↓ by somatostatin, glucose-dependent insulionotropic peptide (GIP), prostaglandin, secretin

31

Source of pepsin

Chief cells (stomach)

32

Action of pepsin

Protein digestion

33

Regulation of pepsin

↑ by vagal stimulation and local acid

34

Source of bicarbonate

- Mucosal cells (stomach, duodenum, salivary glands, pancreas)
- Brunner glands (duodenum)

35

Action of bicarbonate

Neutralizes acid

36

Regulation of bicarbonate

↑ by pancreatic and biliary secretion with secretin