Liver
JAUNdicE This means yellowish discolouration hyper-bilrubinemia.
of the skin , mucous membrane and sclera due to
S. bilirubin must be > 2.5-3 mg/dL to give clinical Jaundice.
Bilirubin metabolism - RBCs ~ heme-» bileverdine ~ indirect bilirubin.
.i,
Bileverdine ..-
Heme..-
RBCs
(unconjugated)
- The bilirubin passes into three steps.
Uptake
of indirect bilirubin through Y and Z receptors in the liver.
Conjugation
and
Urobilinogen (enterohepatic circulation)
Secretion:
Conjugation occurs in the liver by glucouronyl transferease and the conjugated bilirubin is secreted with the bile into the small intestine in the form of stercobilinogen which passing into three directions: •
Part of it enters the enterohepatic circulation.
•
Another part escapes to the systemic circulation reaching the kidney and secreted in urine (urobilinogen).
•
Blood
Urobilinogen (4 mglday)
1
Urobilin
Large . Stercobilinogen intestine (100-200 mglday)
l
Stercobilin
The last part passes to the large intestine to be transformed into stercobilin.
Causes 01 indirect hyperbilirubinemia: Stool (Unconjugated hyperbilirubinemia) Indirect> 80-85% of the total bilirubin.
1- Haemolysis of RBCs (prehepatic jaundice} 2- Uptake defect: Gilbert's syndrome (hereditary). 3- Conjugation defect: • Crigler-Najjar syndrome. • Abnormal steroid in maternal
milk
-7
inhibit enzyme of conjugation (breast milk jaundice).
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