Liver and Bilirubin Flashcards
Functions of the liver (Several hundred known!) Name a few
Metabolism Excretion Hematologic Immunologic Detoxification Storage
Bilirubin: Normal metabolism
Old RBC Destroyed –> Heme –> Bilirubin –> +Albumin –> Unconjucated bilirubin –> LIVER
(In liver unconjugated bilirubin is conjugated) –> intestine –> reducded to urobilinogen –> POOP OR –> Enterohepatic Circulation to be recirculated –> Systemic circulation –> kidney –> PEE
When bilirubin is REVERSIBLY/IRREVERSIBLY bound to albumin, it is called _________.
REVERSIBLY. UNCONJUGATED bilirubin.
Unconjugated bilirubin is:
water (soluble/insoluble)
(toxic/non-toxic) to cells
(passable/too large to pass) glomerular BM
sparingly water soluble
toxic
too large to pass
The liver rapidly clears _______ from the bloodstream.
Unconjugated bilirubin
In the liver, _____ is conjugated into ______ by the liver enzyme named _______
Bilirubin, conjugated/direct bilirubin, Glucoronyl Transferase
Conjugated bilirubin is:
water (soluble/insoluble)
(toxic/non-toxic) to cells
(passable/too large to pass) glomerular BM
relatively water soluble
non-toxic
passable
Conjugated bilirubin spills into bloodstream only when
there is injury of the liver cells, which interferes with transfer of bilirubin to bile canaliculi
You see conjugated bilirubin in the plasma =
Liver Cell Damage! Arg!
What kind of bilirubin is found in the urine?
ONLY conjugated!
When will you see both conjugated and unconjugated bilirubin in the plasma?
massive hemolysis
In the intestines, bilirubin is reduced by bacteria to ________
urobilinogen (UBG)
How much urobilinogen is absorbed from the colon and returned to the liver and re-excreted by liver cells into bile?
20%
How much of the urobilinogen is reabsorbed and remains in the plasma and is excreted in the urine?
A small fraction
What are the two tests for Lab analysis of bilirubin?
Total bilirubin test: measures conjugated and unconjugated forms
Direct Bilirubin test: measures only conjugated
How do you measure Unconjugated Bilirubin?
Total - Direct = Indirect = Unconjugated
When would you use bilirubinometers?
To measure total bilirubin ONLY in neonatal populations. Wont work with adults because of lipochromes such as carotene in adult serum that cause a strong pos. interference
What are things than can screw with your billirubin specimen collection?
Hemolysis causes falsely decreased results
Want to get a fasting so it is free of lipemia
Light causes falsely decreased results
Causes of hyperbilirubinemia
increased bilirubin load on liver cell, distubance in uptake of bilirubin within liver clel, distrubance in transport of bilirubin, defects in conj., defects in excretion, hepatocellular damage, obstruction
Inc. in plasma unconjugated bilirubin
Hemolytic disease, Genetic errors (Gilbert’s syndrome, grigler-naijar syndrome, lucey-driscoll syndrome) Physiologic jaundice of newborn, ineffective erythropoiesis, drugs competing for glucuronide
Inc. in plasma conjugated billirubin
Cholestasis, genetic errors, biliary atresia, hepator cellular damage
Prehepatic disease:
Inc. Unconjegated bili
Normal Conjugated bili
Inc. Urine UBG
NO Urine bilirubin
Posthepatic disease
Inc. Conjugated bili Normal Unconjugated bili Inc Urine bilirubin NO Urine UBG FECES: Chalky white
Hepatic disease (Post-conjugation transport defect)
Inc. Conjugated bili
Normal unconjugated bili
Inc Urine bilirubin
Urine UBG normal or increased?
Hepatic disease (Bilirubin conjugation failure)
Inc. Unconjugated bili
Normal Conjugated
Neg. urine results
Chalky white feces
Aminotransferases
AST=SGOT and ALT=SGPT
- AST measurement:
2. ALT measurement:
- MI, hepatocellular disorders, skeletal muscle involvement
2. hepatic disorders only
5 isoenzymes of LD that have tissue specificity
LD-1 and 2 - Heart, RBC (renal cortex)
LD-3 - non-specific, lung, lymphocytes, spleen, pancreas
LD-4 and 5 - Liver, skeletal muscle
