Gut Peptides

Question 1

What is the enteric endocrine system?

Answer 1

This is the collective term for the endocrine cells of the GIT, consisting for 30 hormones

Question 2

What is the main function of the enteric endocrine system?

Answer 2

Regulate the GIT secretion and movement

Question 3

What are the 3 categories of GIT hormones?

Answer 3

gastrin family
secretin family
others

Question 4

Which hormones belong to the gastrin family?

Answer 4

gastrin
CCK

Question 5

Which hormones belong to the secretin family?

Answer 5

secretin
glucagon-like peptide
vasoactive intestinal polypeptide
gastric inhibitory peptide

Question 6

Which hormones belong to the other family?

Answer 6

peptide YY
ghrelin
motilin
somatostatin

Question 7

Which cells produce gastrin?

Answer 7

G cells

Question 8

What are the functions of gastrin?

Answer 8

Stimulates gastric acid, pepsin, insulin and histamine secretion
Promotes the growth of gastric mucosa and intestinal mucosa
Stimulates gastric motility
Stimulates the mass movement of the large intestine

Question 9

Which tumour results in the secretion of high concentrations of gastrin?

Answer 9

Gastrinoma

Question 10

What is the effect of high concentration of gastrin?

Answer 10

The high levels of gastrin stimulate acid release, leading to the stomach and small intestinal ulcers that may burst
High levels of stomach acid can also cause diarrhoea because the lining of the small intestine becomes damaged

Question 11

What are the effects of low gastrin concentrations?

Answer 11

Increases the risk of infection within the gut, due to decreased mucosal proliferation of the stomach and small intestine
May limit the ability of the stomach to absorb nutrients

Question 12

Which cells produce cholecystokinin?

Answer 12

I cells of duodenum and jejunum

Question 13

What are the functions of CCK?

Answer 13

Stimulate contraction of the gall bladder to cause bile release
Stimulate pancreatic secretion rich in enzymes and augments secretin action
Inhibit gastric acid secretion and gastric motility
Delays gastric emptying

Question 14

Which cells produce secretin?

Answer 14

S cells of the duodenum

Question 15

What are the functions of secretin?

Answer 15

Stimulate pancreatic secretion rich of HCO3 and augments CCK action
Stimulates bile secretion
Reduces gastric acid secretion and gastric motility
Stimulates contraction of the pyloric sphincter

Question 16

Which cells produce GIP?

Answer 16

K cells of the duodenum and jejunum

Question 17

What are the functions of gastric inhibitory peptide?

Answer 17

Inhibits gastric acid secretion and gastric motility
Enhances insulin release in response to infusions of glucose

Question 18

Which cells produce VIP?

Answer 18

Mucosal cells of jejunum

Question 19

What stimulates the secretion of GIP?

Answer 19

The presence of lipid in the duodenum

Question 20

What stimulates the secretion of vasoactive intestinal polypeptide?

Answer 20

Ingestion of a fatty meal

Question 21

What are the functions of vasoactive intestinal polypeptide?

Answer 21

Stimulates intestinal secretion of electrolytes and water
Induces vasodilation to decrease blood pressure
Inhibits gastric secretion and GI motility
Inhibits absorption from the intestinal lumen
Induces relaxation of the LES, stomach and gall bladder

Question 22

Which cells produce GLP?

Answer 22

L cells of the small intestine and large intestine

Question 23

What are the types of glucagon-like peptide?

Answer 23

GLP-1
GLP-2
GLP-3

Question 24

What are the functions of glucagon-like peptide?

Answer 24

GLP-1 inhibits gastric secretion, gastric emptying, pancreatic secretion and also decreases food intake
GLP-2 stimulates proliferation of intestinal epithelial cells and increase digestion, absorption, and blood flow

Question 25

Which cells produce peptide YY?

Answer 25

L cells in the small intestine together with GLP-1

Question 26

What stimulates the release of peptide YY?

Answer 26

Presence of food (fats and proteins) in the GIT Stimulated by digestive juices and CCK

Question 27

What are the functions of peptide YY?

Answer 27

Reduces appetite Increases the feeling of satiety (fullness after eating) Decreases GI motility

Question 28

What are effects of abnormally high peptide YY concentrations?

Answer 28

Decreases in appetite and food intake It is associated with diseases where there is dramatic weight loss - anorexia nervosa and coeliac disease

Question 29

What is the effects of abnormally low peptide YY concentrations?

Answer 29

Increases appetite and food intake It can be seen in obesity and before the onset of T2DM

Question 30

Which cells secrete somatostatin?

Answer 30

S cells of the GIT mucosa

Question 31

What are the functions of somatostatin?

Answer 31

It reduces gastric acid secretion and GI motility Inhibits the secretion of gastrin, secretin, motility Inhibits exocrine and endocrine pancreatic secretions

Question 32

What are the effects of abnormally high concentrations of somatstatin?

Answer 32

May result in the formation of gallstones Intolerance to fat in the diet and diarrhoea

Question 33

Which cells produce motilin?

Answer 33

Mo cells mainly in the duodenum and jejunum

Question 34

What are the functions of motilin?

Answer 34

Stimulates the production of pepsin Controls the inter-digestive migrating concentrations by the upper GIT It sweeps the stomach and small intestine clear of undigested material to prepare for the next meal It stimulates the stomach contraction and accelerates gastric emptying

Question 35

Which cells produce ghrelin?

Answer 35

Endocrine cells in the stomach

Question 36

When does the concentration of ghrelin increase?

Answer 36

It increases before eating or when fasting

Question 37

What are the functions of ghrelin?

Answer 37

Increases food intake Stimulates appetite Promotes fat storage

Question 38

What are effects of abnormally high concentrations of ghrelin?

Answer 38

Increased appetite and body weight gain It is usually lower in people with higher body weight compared to lean people Anorexia nervosa, which may be compensatory response to weight loss

Question 39

What are the effects of abnormally low concentrations of ghrelin?

Answer 39

Seen after gastric bypass surgery Associated with weight loss