Gut Hormones

Question 1

What are the two forms of gastrin

Answer 1

G34

G17

Question 2

When is gastrin produced

Answer 2

Antrum

Question 3

When is gastrin released

Answer 3

High pH

Stimulated by proteins, peptides and amino acids

Question 4

What are the two actions of gastrin

Answer 4

Acid secretion from parietal cells

Growth promoting effects on gastric mucosa

Question 5

Hypergastrinaemia occurs in…

Answer 5

Decreased acid production (atrophic gastritis)

Overuse of PPI

zollinger ellison syndrome

Question 6

Which cells secrete CCK and where

Answer 6

I cells

Small intestine

Question 7

CCK release is stimulated by…

Answer 7

Ingestion of fat and protein

Question 8

What are the 3 actions of CCK

Answer 8

Gallbladder contraction and bile acid release

Regulates gastric emptying and bowel motility to induce satiety

Regulates meal stimulated pancreatic secretion

Question 9

Which conditions are associated with a low CCK

Answer 9

Coeliac disease

Bulimia

Question 10

Which condition are CCK levels reportedly high

Answer 10

Chronic pancreatitis

Question 11

Which cells secrete secretin

Answer 11

S cells

Question 12

When is secretion released

Answer 12

Stimulated by acid in duodenum

Question 13

What are the actions of secretin

Answer 13

Pancreatic and bicarbonate secretion neutralising acidic chyme in intestine

Inhibits gastric acid, gastric secretions and intestinal motility

Aids osmoregulation of hypothalamus and pituitary

Question 14

Where is VIP released from

Answer 14

Neurones in gut, pancreas

Question 15

What is the action of VIP

Answer 15

Vasodilator = smooth muscle relaxation

Secretion of electrolytes into lumen

Neuromodulator of sphincters of GI tract

Question 16

What does a lack of VIP lead to?

Answer 16

Hirschsprungs

Question 17

What does excessive VIP lead to

Answer 17

WDHA

Watery diarrhoea
Hypokalaemia
Achlorhydria

Question 18

Which cells produce glucagon

Answer 18

Alpha cells in pancreas

Question 19

What is the action of glucagon

Answer 19

Regulates glucose homeostasis:

Gluconeogenesis
Glycogenolysis
Lipolysis

Question 20

Where is gastric inhibitory polypeptide released

Answer 20

K cells in duodenum, jejunum mucosa

Question 21

What is the action of GIP cells

Answer 21

Inhibit gastric acid secretion
Stimulate insulin release in hyperglycaemic state

Augments triglyceride storage contributing to fat accumulation

Question 22

Where is pancreatic polypeptide released

Answer 22

Endocrine cells of pancreas

Question 23

Describe pancreatic polypeptides actions

Answer 23

Self regulation of pancreatic secretory activity

Affects hepatic glycogen levels and GI secretions

Question 24

Somatostatin is produced in the…

Answer 24

D cells

Question 25

When is somatostatin released

Answer 25

Influenced by pH Mechanical stimulation Dietary component (fat, protein, glucose)

Question 26

Actions of somatostatin

Answer 26

Regulate gastric acid secretion Reduce pepsinogen secretion Inhibit bicarbonate and pancreatic enzyme release Reduce bile flow Reduce gut motility Reduce splanchnic blood flow

Question 27

Lepton blood levels reflect total body fat stores, but where is it released from

Answer 27

Chief and adipose cells in stomach

Question 28

How does lepton regulate food ingestion?

Answer 28

Lowers neuropeptide Y levels (a potent stimulator of food intake within the brain)

Question 29

Where is ghrelin produced

Answer 29

P/D1 cells in gastric fundis, pancreas, pituitary

Question 30

Describe the actions of ghrelin

Answer 30

Stimulate gastric contraction Enhance stomach emptying Initiation of ingestion LEVELS HIGH WHEN HUNGRY

Question 31

Where is motilin produced

Answer 31

Endocrine cells in duodenum

Question 32

Motilins secretion is periodic and not affected by food ingestion, but what are its actions?

Answer 32

Increase migrating myoelectric complex of GI motility Stimulate pepsin production Peristalsis in small intestine in preparation for next meal

Question 33

What does substance P primarily mediate?

Answer 33

Neurogenic inflammation

Question 34

What is the role of substance P

Answer 34

Activate vomiting reflex Involvement in nociception High levels of substance P found in UC and Crohn's

Question 35

In relation to satiety signals, what is the role of CCK

Answer 35

Delays gastric emptying Signals termination of food ingestion

Question 36

In relation to satiety signals what is the role of ghrelin

Answer 36

Initiates meal ingestion Levels rise rapidly before a meal and fall rapidly afterwards

Question 37

In relation to satiety signals what is the role of glucagon like peptide

Answer 37

Delays gastric emptying Increases satiety

Question 38

In relation to satiety signals what is the role of leptin

Answer 38

Reduced food intake Produces greater reduction in body weight

Question 39

In relation to satiety signals what is the role of neuropeptide Y

Answer 39

Increases food intake Increases proportion of food stored as fat

Question 40

In relation to satiety signals what is the role of peptide YY

Answer 40

Reduced calorie intake Inhibits gastric motility Increases water and electrolyte absorption in colon