NME 2.3 Flashcards
which two types of secretion are present in pancreatic juice?
- enzyme rich secretion from acinar cells
- aqueous alkaline secretion from ducts
what happens if the duct is ligated near the acinar?
- cause acinar cell degeneration
- secretion of alkaline components is unaffected
- secretion of enzymes is reduced
what are the 6 ions of pancreatic juice composition?
- sodium
- potassium
- bicarbonate
- magnesium
- calcium
- chloride
is pancreatic juice acidic or alkali and why?
alkali because of high content of bicarbonate
function of pancreatic juice?
- protects intestinal mucosa from excess acid
- provide a alkali environment for fat absorption through micelles
- provide alkali environment for pancreatic enzymes
what does the pancreatic acini produce?
- NaCl secretion
- isotonic solution
what does the pancreatic duct produce?
- secrete large volume of fluid
- bicarbonate secretion
- water permeable so water follow anions
describe pancreatic secretion in acini?
- sodium is pumped out of cell by sodium potassium ATPase
- potassium will leak out of cell
- makes cell have high concentration of chloride
- chloride flow into the duct down concentration gradient
which three things will increase calcium and activate protein kinases?
- M3
- ACh
- CCK
difference between ducts in saliva and pancreas?
- pancreatic duct water permeable while salivary duct are water impermeable
describe pancreatic secretion in ducts?
- sodium allows movement of bicarbonate through same channel
- carbonic anhydrase combined carbon dioxide with water to form carbonic acid
- carbonic acid dissociates H+ ions and form bicarbonate
- H+ will be taken up the blood
- more CFTR active will cause more bicarbonate is produced
what two things stimulate CFTR channel?
- ACh
- secretin
how does ACh stimulate CFTR channel?
stimulate calcium release
how does secretin stimulate CFTR channel?
increase the cAMP
what is amylolytic?
- carbohydrate digestion
- examples: amylase
what is lipolytic?
- fat digestion
- example: lipase and phospholipase
what is nucleolytic?
- nuclei acid digestion
- example: DNAse and RNAse
what is proteolytic?
- protein digestion
- example: trypsin, chymotrypsin and elastase
what is normally seen in pancreatic dysfunction?
- lipolytic problem therefore unable to digest lipids
what happens to pancreatic secretions during the cephalic and gastric phase?
- vagus timulate short term acinar
- vagus also stimulate ductal secretion but lesser degree
what happens to pancreatic secretion during intestinal phase?
- hormones provide strong stimuli and long term secretion
stimulation through the vagus nerve
what does secretin do for hormonal control?
- stimulate secretion of alkaline aqueous component
what does CCK-PZ do for hormonal control?
- stimulate secretion of enzyme component
where are CCK and secretin produced?
by the APUD cells in duodenal mucosa
what three things increases enzyme protein synthesis?
- CCK
- gastrin
- ACh
how does CCK, gastirn and ACh increase enzyme synthesis?
- increase in phosphatidylinositol turnover
- increase intracellular calcium concentration
what does somatostatin do?
- inhibit release of exocrine gland
- inhibit release of enzyme secretions
- inhibit release of insulin and glucagon
- inhibit release of CCK, gastrin and secretin
what three things stimulate release of somatostatin?
- CCK
- Gastrin
- Secretin
what does the release of ACh stimulate?
- acinar cells to produce enzymes
- duct cells produce bicarbonate
what does the acid stimulate?
- stimulate s cells
- cause secretin to be produced
what are the 5 enzyme activated by trypsin?
- chymotrpsinogen
- proelastase
- procarboxypeptidase
- prophospholipase A
- procolipase
what does enzyme Y do?
- help as a protective mechanism for the pancreas
- stop activation of trypsin
what are kazal inhibitor?
- inhibits small amount of trypsin going into the duct
what does alkaline pH and low calcium concentration promote for protective mechanism
- degradation of trypsinogen
