Humonal regulation of digestion Flashcards
What does parasympathetic nerve do in terms of digestion
Stimulates GI tract activity like:
secretion of digestive jucies
increased motoloty of the stomach
slowing down movement of food to SI
What are the endocrinal cells located within the GI tract called
Enteric endocrine system
What are enteroendocrine cells
Produces and release GI hormones
What are the intestinal enteroendocrine cells
G cells
S cells
Enterochromaffin-like cells
What do g cells release and what does it do
G cells release gastrin
stimulate gastric acid secretion
What do S cells secrete
What do they do
Secrete secretin from the SI
stimulate exocrine pancreatic secretion
like water and bicarbonate ion secretion
What do enterochromaffin-like cells secrete
What od they do
Secret histamine
Stimulate gastric acid secretion
What are gastric enteroendocrine cells
Chief cells
Parietal cells
What do chief cells secrete
secrete enzymes
What do Parietal cells secrete
Secrete HCL in the sotmach
What are pancreatic enteroendocrine cells called and what do they produce
Beta cells
Produce insulin
What does gastrin inhibitory peptide do
inhibits gastrin secretion and motility and stimulates secretion of insulin
What does somatostatin do
inhitnits gastrin and histamine secretion
What does cholecystokinin do
Stimulates secretion of pancreatic enzymes and contraction and emptying of gall bladder
What is the purpose of the cephalic phase of digestion
activation of the neural centre by smell, sight, and taste prepares mouth and stomach for food intake
What occurs in the cephalic phase
Smell, sight, taste, or thoughts of food activate the CNS
Impulses sent down the Vagus nerve to the submucosal plexus where:
mucous cells release mucous
chief cells release pepsinogen
parietal cells release HCL
G cells release gastrin
What activates the gastric phase
Stretch receptors are activated by the food pushing on the stomach wall
Elevated pH also activates chemoreceptors
What activates mixing waves of stomach
Gastrin and submucosal and myenteric plexus
What does gastrin do in gastric phase
Secreted from G cells
Increases secretion of HCL into stomach
Increases release of histamine
What does histamine do in gastric phase
Secreted from enterochromaffin-like cells
Increases HCL acid in the stomach
What does somatostatin do in gastric phase
Produced by D cells in stomach
Secreted in response to acidic pH
Inhibits gastrin and histamine secretion
Where are gastrin receptors predominately found
Parietal and ECL cells
What does secretin do in intestinal phase
inhibits secretion of gastric acid from parietal cells
Stimulates production of bicarbonate solution from ductal cells
What does Cholecystokinin do in intestinal
Released when fats/protein present in SI
Stimulates release of pancreatic enzyme and bile
