Flashcards in GIT Deck (33):
What hormone is stimulated by fat in small intestine?
What cells produce cholecystokinin ?
Gut endocrine cells (I cells) of the mucosa of the small intestine
In the stomach what release pepsinogen?
What activates pepsinogen?
1. Acidic pH
What is pepsinogen?
An inactive pre cursor of the proteolytic enzyme pepsin
The breakdown of complex food stuff is accomplished by?
Complex starches are mainly digested by enzymes secreted from?
Pancreas (alpha amylase)
Which process transports AA across the luminal surface of the epithelium that lines the small intestine?
Co transport with NA ion
How does the stomach not digest itself?
1. Gastric mucosal cells transport H ions out of gastric mucosa
2. Pepsin is stored as pepsinogen so it will only be released when needed and does not digest the bodies own protein in stomach lining
How is stored fat usually transported from 1 side of the body to the other?
Free fatty acids
What is the concentration of free fatty acids in plasma?
What is an essential AA?
An amino acid that cannot be synthesised de novo and must therefore be supplied by the diet
What are the 9 essential AA?
What are the conditionally essential amino acids?
What is the meaning of a conditionally essential amino acid?
Not normally require in the diet but must be supplied exogenously to specific populations that do not synthesise adequate amounts
What hormones are secreted by the duodenum?
What does secretin do?
1.Regulates water homeostasis throughout the body
2. Helps regulate the ph of the duodenum by inhibiting the secretion of gastric acid from the parietal cells of the stomach; and
3. stimulating the production of bicarbonate from the centroacinar cells and intercalated ducts of the pancreas
Which cells secrete intrinsic factor?
Where are kupffer cells found?
Have phagocytic properties
What do parietal cells secrete ?
30% of acid production
Vagal cholinergic stimulation causing secretion of HCL and gastrin release from G cells
60% of acid produced
10% of acid production
Factors increasing gastric acid production
1. Vagal nerve stimulation
2. Gastrin release
3. Histamine release (indirectly following gastrin release) from enterochromaffin cells
Factors decreasing gastric acid production
1. Somatostatin (inhibits histamine release)
What cells secrete secretin ?
S cells of duodenum - located in the crypts of lieberkuhn
What goes gastrin do?
1. Increase HCL
2. Increase pepsinogen
3. Increase IF
4. Increase gastric motility
5. Trophic effect on gastric mucosa
What cells secrete gastrin?
G cells in Antrum of the stomach
What cells secrete CCK?
I cells in upper small intestine
What does CCK do?
1. Increase secretion of enzyme rich fluid from the pancreas
2. Contraction of the gallbladder and relaxation of sphincter oddi
3. Decrease gastric emptying
4. Trophic effect on pancreatic acinar cells
5. Induces satiety
What does VIP do?
1. Stimulates secretion by pancreas and intestines
2. Inhibits acid and pepsinogen secretion
What does somatostatin do?
1. Decreases acid and pepsin secretion
2. Decreases gastrin secretion
3. Decreases pancreatic enzyme secretion
4. Decreases insulin and glucagon secretion
5. Inhibit strophic effect of gastrin
6. Stimulates gastric mucus production