Bile,Gall Bladder And Gallstones Flashcards
What is function of gallbladder?
Storage and concentration of bile
What does pancreatic juice consist of?
Bile salts, bile pigments and dissolved substances in alkaline electrolytes
Describe the flow of bile?
Hepatocytes-> bile canaliculi(merge to form ductules)-> terminal bile ducts-> common bile ducts
What are 2 different cell types that secrete bile?
Hepatocytes and epithelial cells of bile ducts
What does hepatocytes secrete?
Cholesterol, lecithin, bile acids, bile pigments (bilirubin,biliverdin, urobilin)
What does epithelial cells of bile ducts secrete?
Bicarbonate rich salt solution
What influences the secretion of bicarbonate rich salt solution?
Secretin
When is Sphincter of Oddi contracted?
During periods of fasting
When is Sphincter of Oddi relaxed?
During and after meals
What substances are secreted across bile canalicular membrane?
Bile acids Phosphatidylcholine Conjugated bilirubin Cholesterol Xenobiotics
Describe the composition of hepatic bile?
97% water
Cholesterol, lecithin, bile acids, bile pigments etc
Describe the composition of gallbladder bile?
89% water
HCO3-, Cl-, Ca2+, Mg2+, Na+, cholesterol, bilirubin, bile salts etc
What are bile acids made from?
Made from cholesterol
What is bile acids secreted into and conjugated to?
Secreted into bile and conjugated to glycine or taurine
What are 4 major bile acids found in humans?
Cholic acid=50%
Chenodeoxycholic acid=30%
Deoxycholic acid=15%
Lithocholic acid=5%
What are primary bile acids? Where are they formed?
Chenodeoxycholic acid
Cholic acid
Formed in the liver
What are secondary bile salts? Where are they formed?
Lithocholic acid
Deoxycholic acid
Formed in the colon
What converts the primary bile acids to secondary bile acids?
Anaerobic intestinal bacteria
Chenodeoxycholic acid -> lithocholic acid
Cholic acid-> deoxycholic acid
What are main functions of bile/bile acids?
Elimination of cholesterol to bile acids
Reduce the precipitation of cholesterol in gallbladder; bile acids and phospholipids help solubilise cholesterol in bile
Facilitate absorption of fat soluble vitamins (ADEK)
Regulate their own transport and metabolism via enterohepatic circulation
Facilitate digestion of TGs
What does CCK trigger in gallbladder?
Triggers contractions
What does CCK cause in Sphincter of Oddi?
CCK causes relaxation
What secretin in liver stimulate?
Stimulates duct cells
What controls contraction of gallbladder and release of bile into duodenum?
Control of gallbladder motility
Presence of fatty meal stimulates secretion of CCK
Relaxation/opening of Sphincter of Oddi
What is enterohepatic circulation?
Recycling process of bile acids
Recycling pathway from intestine to liver and back to intestine
Where is bile acids, lecithin (phospholipids synthesised)?
Synthesised in liver
What does interruption of enterohepatic circulation cause?
Excess synthesis of bile salts by liver
Kidneys will excrete the synthesised bile salts
What are bile salts?
Bile compounded with a cation e.g. Na+, cholesterol and phospholipids
What causes increased cholesterol?
Liver secretes excess
Reabsorption of salt and water
What are 2 types of gallstones?
Cholesterol stones (85%): obesity; decrease bile acids vs decrease phospholipids Calcium bilirubinate stones: due to increase conjugated bilirubin (haemolytic anaemia)
What are factors involved in gallstone formation?
Bile stasis
Deceased amount of bile acids due to malabsorption
Chronic infection
Super saturation of bile with cholesterol
Diagnoses of gallstones
Ultrasonography
Cholescintigraphy
Endoscope retrograde cholangiopancreotography
What are the clinical features of gallstones?
Gallstone in cystic bile duct
Gallstone blocking common bile duct
Gallstone blocking duodenal papilla
