Hormonal Control Of The Gut Flashcards
1
Q
What are Paracrine hormones?
A
Act on neighbouring cells - diffuse short distance
2
Q
Describe neurocine hormones in the GI system
A
- peptides released by neurones in the GI tract after an AP
e.g. gastrin releasing peptide
3
Q
Describe endocrine hormones in the GI system
A
- peptides released into portal circulation > pass through the liver > enter systemic circulation > delivered to where it needs to be
e.g. gastrin, cholecystokinin + secretin
4
Q
Examples of endocrine hormones in the GI system
A
Gastrin
Cholecystokinin
Secretin
5
Q
Example of a paracrine hormone in the GI system
A
Somatostatin
6
Q
Example of neurocrine hormone in the GI system
A
Gastric releasing peptide
7
Q
Outline enteroendocrine cells
A
- Activated due to stretch or eating food
- found between epithelial cells of the gut in the mucosa from the stomach to the colon
- release endocrine + paracrine hormones
8
Q
Describe cholecystokinin release
A
- released from I cells in the duodenum and jejunum
-
stimulated by fats + proteins
Effect: - contraction of gall bladder + stimulates pancreas > increase pancreatic/gallbladder secretions
- relaxes the sphincter of Oddi
9
Q
Describe secretin release
A
- released by S cells in the duodenum
-
stimulated by H+ and fatty acids (from the acidic chyme)
Effect: - increases the release of HCO3 from pancreas + gallbladder
- decreases gastric acid secretion
10
Q
What is the Sphincter of Oddi?
A
Muscular valve surrounding the exit of the bile duct + pancreatic duct into the duodenum
11
Q
Describe gastric inhibitory polypeptide release
A
- released by cells in the duodenum + jejunum
-
stimulated by sugars, aa + fatty acids
Effect: - increases insulin
- decreases gastric acid secretion
12
Q
Describe the action of somatostatin
A
- switches off G cells > decrease in gastrin release
- stimulated when low pH is detected
