Liver Flashcards
functions of the liver
carb metabolism, fat metabolism, source of cholesterol, source of AA and proteins, storage, detoxification, and immune function
what are some differences in healthy vs. injured cells of liver
in injured, there are activated HSC, loss of fenestrate, activated kupffer cells, deposition of scars of ECM
liver composed of
lobules
what provides the hepatic blood
75% - portal vein
25% - hepatic artery
what provides the hepatic blood
75% - portal vein
25% - hepatic artery
sinusoids drain into
central veins which unite to form hepatic veins
functional unit of liver
acinus
zones of the liver
zone I: cells closest to the arteriole and have the highest delivery of oxygen
zone II: transition zone
zone III: cells furthest away from the arteriole and oxygen and nutrient supply is the least
zones of the liver
zone I: cells closest to the arteriole and have the highest delivery of oxygen
zone II: transition zone
zone III: cells furthest away from the arteriole and oxygen and nutrient supply is the least
zone most susceptible to drug toxicity
zone III
zone that will preferentially undertake oxidative metabolism, ureagenesis, gluconeogenesis, and bile production
zone I
zone that will undertake glycolysis, ketogenesis, detoxification, xenobiotic metabolism
zone III
largest fraction of total fluid secretion that makes up bile consists of
isotonic fluid with electrolyte concentration favoring plasma
epithelial cells lining the biliary tree secretes what
HCO3 in response to high levels of secretin (like pancreas)
hepatic bile is compromised of secretions from where
hepatocytes and biliary tree
hepatic bile is compromised of secretions from where
hepatocytes and biliary tree
what type of fluids come from the hepatocytes and biliary tree
hepatocytes - canalicular bile made up of organic molecules, NaCl/water
biliary tree - ductular bile made up of NaHCO3/water
amount of bile made per day
500mL
how does bile facilitate fat digestion
emulsification and solubilization through formation of mixed micelles
is bile alkaline or acidic
alkaline to help to neutralize the gastric acid
what does mixed micelle do to facilitate fat digestion
enhances efficiency of lipase action and delivery of fat digestion products to absorptive enterocytes
difference between kidney and bile in excretion of compounds
kidney helps to excrete smaller water soluble compounds while bile helps to excrete larger hydrophobic molecules
can fat still be absorbed without bile salts
yes but it is not as efficient
70% of bile is made up of
bile acids
70% of bile is made up of
bile acids
20% of bile solids are
phospholipids aka lecthins
cholesterol is what percentage of bile solids
4%
what are the amphipathic component of bile
phospholipids and bile acids (aka bile salts) which together form mixed micelles
what is hydrophobic component of bile
cholesterol and must be in center of micelle to be dissolved
% of primary and secondary bile acids in bile
primary - cholic (50%) and chenodeoxycholic acid (30%)
secondary - deoxycholic (15%) and lithocholic acid (5%)
% of primary and secondary bile acids in bile
primary - cholic (50%) and chenodeoxycholic acid (30%)
secondary - deoxycholic (15%) and lithocholic acid (5%)
what makes the secondary bile acids less soluble less than primary bile acids
the loss of polar OH- groups
solubilize hydrophobic molecules and promote their diffusion to the absorptive membrane of the enterocytes
micelles
since the bile pool is lower than needed to assimilate the lipid content of a typical meal, what is the compensation
bile acids are recycled and total bile pool is secreted twice during a meal and about 6-8 times a day through enterohepatic circulation of bile acids
major reabsorption of bile acid is where
distal ileum via Na+/bile acid cotransporter
bile acids that are deconjugated are absorbed where
jejunum by simple diffusion due to higher lipid permeability
rate limiting step in secretion of bile acids
transport across the canalicular membrane via facilitated diffusion
