文档介绍：Jaundice
Definition
Accumulation of yellow pigment in the skin and other tissues (Bilirubin)
Bilirubin Metabolism
Bilirubin formation
Transport of bilirubin in plasma
Hepatic bilirubin transport
Hepatic uptake
Conjugation
Biliary excretion
Enterohepatic circulation
Bilirubin
RBCs
Senecent RBCs
Iron
hemoglobin
Globin
Bilirubin Biliverdin heme
Hepatic Hemoproteins
nonhemoglobin heme
nonhemoglobin hemoprotein
Premature destruction of newly formed RBCs
C
MHO
R
CBR
1-5%
Chiefly
70+%
20%
Bilirubin formation
120ds
Transport of Bilirubin in Plasma
Albumin + UB UB ~ plex
Molar
Ratio
Bilirubin
Bilirubin
Plasma protein
Albumin
H affinity binding sites
L affinity binding sites
can be replaced by
anic anions
PH
UB
2:1
>2:1
CB
1. Hepatic uptake of Bilirubin
UCB~plex Separated
Bilirubin
Plasma membrane of the liver
(be) taken up
MTA (receptor ?)
Transfer across
Microvillar membrane
Excretion of Bilirubin
Bile canaliculus
of Bilirubin
UCB
carrier
protein
ER
CBGA
CB
(be) bound to
transfer
Conjugation
(catalized by
UDPGT)
Z protein
ligation (Y protein)
Hepatic Bilirubin Transport
(lipid soluble)
(water soluble)
UDPGT: Uridine Diphosphate Glucuronyl Transferase
UCB: because of its tight albumin binding and lipid solubility, it is not excreted in urine.
CB: is less tightly bound to albumin and is water soluble, so it is filtered at the glomerulus and appears in the urine.
Entero-hepatic circulation
CB
B and I
Urobilinogens (coloress)
be degraded
Bacterial Enzymes
feces (feceal urobilinogens)
Reabsorbed
plasma
circulation
kidneys
50-200 mg/d
mostly
urine urobilinogen
4 mg/d
T
liver
Bile
feces
re-excreted
excreted
90%
trace
20%
The serum of normal adults contains 1 mg of bilirubin per 100 ml.
In healthy adults
The direct fraction is usually < mg/100 ml
The indirect fraction is usually < mg/100 ml
Pathophysiologic classification of Jaundice
Hemolytic Jaundice
Hepatic Ja