last lecture info Flashcards
what keeps the bacteria in the colon
ileocecal valve
some colon bacteria can ferment undigested carbohydrates to:
short chain fatty acids
(soluble and easily absorbed, nutrient salvage)
what vitamin does the colon bacteria produce
vitamin K
more than 90% of pancreas is:
exocrine
these cells synthesize and secrete hydrolases for digestion
acinar cells
these cells secrete bicarbonate and water
duct cells
luminal digestion of carbohydrate, protein, fat
impaired functions causes maldigestion and malabsorption
pancreatic exocrine secretion
pancreatic exocrine neutralizes gastric H+ by
secreting HCO3- into duodenum (this is what duct cells do)
why doesn’t the pancreas digest itself?
what is also put in place to make sure?
proteolytic enzymes are synthesized, store and secreted as INACTIVE
they are activated in the lumen
(enterokinase and trypsin)
-trypsin inhibitor is stored and secreted with precursors (to make sure trypsin does not activate in pancreas) (could cause acute pancreatitis)
two stimuli for acini cell enzyme secretion in the pancreas:
- cck
- ACh/GRP (vagovegal reflex)
what is the function of the acinar cell
digestive enzyme secretion
CCK function in
stomach:
pancreas:
gallbladder:
sphincter of Oddi:
stomach:
1. stimulates relaxation
2. reduce emptying (a enterogastrone)
3. reduce HCl secretion
pancreas:
acinar secretion
gallbladder:
contraction
sphincter of oddi:
relaxation
two things that stimulate I-cells to secrete CCK into the blood:
(trypsin itself controls its own secretion by metabolizing these two things: the lower the concen of proteins in lumen, more likely these will be digested and the less enzymes will be secreted)
- monitor peptide
- CCK-RP
two stimuli for ductal cells to secrete H2O and HCO3- in the pancreas:
(needs to be basic because it has to neutralize the stomach acid)
- secretin
- Ach
