Gastric Motility and Pancreatic Function Flashcards
what produces a more powerful reaction, the body or the antrum of the stomach?
the antrum due to thick muscle layer
how does contraction of the pyloric sphincter cause more mixing of the antral contents?
it stops the chime from entering the duodenum forcing it back up towards the body causing mixing
what produces the peristaltic rhythm?
pacemakers in the longitudinal layer of muscle
describe the depolarisation produced by slow waves
they are subthreshold and require further depolarisation to produce an action potential
what causes an increase in contraction of the stomach?
> distension of the stomach wall
> gastrin
what in the duodenum will cause inhibition of motility?
> amino acids
hypertonicity
fat
acid
where are brunner’s gland cells located?
in the submucosa of the duodenum
what do brunner’s glands release?
bicarbonate HCO3
how does the duodenum respond when there is acid?
> long and short reflexes cause the release of bicarbonate
secretin is released from s cells which acts on the liver and the pancreas causing bicarbonate secretion, neutralising the acid
what inhibits secretin release?
acid neutralisation (negative feedback)
what do islets of Langerhans produce?
> insulin
glucagon
somatostatin
describe the journey from the lobules connected by intercalated ducts to the duodenum
> intralobular ducts > interlobularduct > main pancreatic duct > common bile duct -through the sphincter of oddi- > duodenum
apart from the main pancreatic duct how else may secretions enter the duodenum form the pancreas?
through the accessory pancreatic duct
what is the exocrine part of the pancreas responsible for?
the digestive function of the pancreas
what do the acini in the pancreas secrete?
digestive enzymes
what do the ducts in the exocrine part of the pancreas secrete?
bicarbonate
what do acinar cells contain to prevent auto-digestion of the pancreas?
digestive enzymes stored as inactive zymoger granules
where are enterokinases found?
bound to the brush border of duodenal enterocytes
what is the function of enterokinase?
it converts trypsinogen to trypsin
what is the function of trypsin?
it converts zymogens to their active forms
name pancreatic enzymes
> nucleases > proteases > elastases > alpha-amylase > phospholipids > lipases
what is the function of alpha-amylase?
it converts starch into maltose and glucose
what would stimulate the release of cholecystokinin?
fatty acid in the duodenum or organic nutrients in the duodenum (neural)
what is the effect of cholecystokinin?
zymogen secretion
