Histology of pancreas, liver, gall bladder Flashcards Preview

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Flashcards in Histology of pancreas, liver, gall bladder Deck (15):

two "parts" of pancreas? what are the fundamental units of each? which predominates?

endocrine- islets of langerhans (mostly in tail). exocrine-acini. Exocrine is vast majority


how are pancreatic proteases activated?

enterokinase in brush border converts trypsinogen to trypsin which then activates the other zymogens


centroacinar cells

line duct and extend into central lumen of acinus. Secrete HCO3-


Three major classes of endocrine cells and their function

Alpha: glucagon (raises blood glucose). Beta: zinc-insulin granules (lowers it). Delta: somatostatin (inhibits insulin and glucagon)


autonomic effect on endocrine pancreas

sympathetic: stimulates glucagon, inhibits insulin. Parasympathetic: stimulates both


organization of classic liver lobule

hexagon with central vein and vessels (hepatic artery, portal vein, bile duct) at each corner. In between are single-layered hepatocytes forming sinusoids through which blood percolates


space of disse

between sinusoidal cell microvilli and the fenestrated endothelium. Basically lymphatic


three surfaces of hepatocyte

2 sinusoidal (basal) surfaces, 4 lateral surfaces, bile canalicular (apical) surface which wrap in "belts around cell" and are sealed by tight jxns


bile constituents

bile salts (cholesterol derivatives) to emulsify. Pigment from glucuronidated bilirubin from heme breakdown. Plasma proteins and IgA


kupffer cells

resident tissue macrophages. Line the sinusoids. Digest old RBCs


lipocytes (ito cells)

in space of disse. store vit A in their lipid droplets


what does liver do with fatty acids

makes them into VLDL in golgi then secretes them into blood


how does gall bladder concentrate bile

Na and Cl enter cells and are pumped out basolateral membrane. Water follow.


unique histology of gall bladder

no muscularis mucosae or submucosa


how is bile released

CCK secreted after meal causes sphincter of Oddi relaxation, gall bladder contraction