jaundice and liver failure Flashcards
why do we produce bile?
- Cholesterol homeostasis. - Dietary lipid/vitamin absorption - Removal of xenobiotics/drugs/endogenous waste product.
what is bile composed of?
- Bile is 97% water and exists in an alkaline solution. - 500ml produced
what cells secrete bile?
60% by hepatocytes 40% by Cholangiocytes in the biliary tree
what are the roles of the bilary tree?
- Alter pH, fluidity and modifies bile. - Facilitates passage of H2O into the bile via osmosis - Reabsorbs glucose and some organic acids - Secretes HCO3 -and Cl into the bile through CFTR. - contribute IgA antibodies
how is bile transported?
- Apical transporters secrete the bile salts and toxins which also govern flow rate of bile
what happens if the transporters stop?
cholestasis
what are examples of the transporters?
BSEP – Bile Salt Excretory Pump ( active transport of the bile acids into the bile ) - MRP1 MDR related proteins
how many bile acids do we have what are they separated into?
- 4 bile salts 2 primary and 2 secondary - primary is converted into secondary Cholic Acid → Deoxycholic Acid Chenodeoxycholic Acid → Lithocholic Acid
whata re 2 main functions of the bile?
- Reduce surface tension of fats. - Emulsify fats
how do bile salts work?
- they form micelles - due to they hydrophilic and hydrophobic nature
issue with bile salts?
- they can be toxic in high concentrations
** look at the anatomy of the gall bladder and biliary tree :
************

what happens at the ampulla of the bile duct?
the sphincter of Oddi controls bile secretion into the 2nd duodenum.
what duct does the cystic duct join?
pancreatic duct before entering the duodenal papilla
what happens when you eat? what hormone is secreted?
Cholecystokinin
what are the functions of Cholecystokinin ?
- Relax the sphincter of Oddi. -Contract the smooth muscle around gall bladder.
what is entrohepatic circulation?
- where the liver cells transfer various substances including drugs from to the plasma to the bile
how does entrohepatic circulation affect drugs?
Can re-activate/prolong drug action - can affect drug dosage
what happens when bile cells undergo entrohepatic circulation?
- 95% of bile salts reabsorbed in the terminal ileum - 5% are converted to secondary bile acids in the colon by colon bacteria - 3g of bile salts at any one time, secreted 2x a meal.
what happens if someone does not have a terminal ileum?
– less resorption = more fatty stool as less bile salt excreted - malabsorption of fat soluble vitamins can cause irritable bowel
what are functions of the gall bladder?
- storage - acidification - concentrates bile bu H2O diffusion
what are the effects of a Cholecystectomy ? ( gall bladder removal )
- Gall Bladder aids digestion but is NOT essential. - they might get bowel problems -so they have to avoid very fatty foods
what is bilirubin?
H2O insoluble, yellow pigment.
what is bilirubin produced from?
- 75% - Hb breakdown – in the spleen - 22% - Catabolism of other haem proteins. - 3% - Ineffective bone marrow erythropoiesis.

