Describe the composition, formation and functions of bile.
Bile is produced by hepatocytes, excretion via cannaliculus and biliary tree. It is stored and concentrated in the gallbladder. Bile contains water, bile acids and bile salts, bile pigments and electrolytes. Some detail was expected regarding each of these and comment on “Primary bile acids”, conjugation with taurine and glycine and production of “bile salts”. It was often not appreciated bacteria in gut produce “secondary” bile acids such as deoxycholate and lithocholic acid. Additional credit was given for discussing “Unconjugated bilirubin” being derived from “heme” component of haemoglobin (85%) is carried via albumin to liver for conjugation via UDP-gluconuryl transferase to “conjugated bilirubin” and that gut bacteria generate water soluble urobilinogen, enterohepatic recycling and excretion in urine.The major role of bile is in lipid, cholesterol and lipid soluble vitamin absorption with a minor role in excretion of bile pigments. It was expected candidates would describe the emulsification of fat via bile salts and lipid micelle formation to facilitate absorption.
Composition of bile:
Formation of bile:
Function of bile:
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