Liver and Bilirubin

Question 1

Functions of the liver (Several hundred known!) Name a few

Answer 1

Metabolism
Excretion
Hematologic
Immunologic
Detoxification
Storage

Question 2

Bilirubin: Normal metabolism

Answer 2

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

Question 3

When bilirubin is REVERSIBLY/IRREVERSIBLY bound to albumin, it is called _________.

Answer 3

REVERSIBLY. UNCONJUGATED bilirubin.

Question 4

Unconjugated bilirubin is:
water (soluble/insoluble)
(toxic/non-toxic) to cells
(passable/too large to pass) glomerular BM

Answer 4

sparingly water soluble
toxic
too large to pass

Question 5

The liver rapidly clears _______ from the bloodstream.

Answer 5

Unconjugated bilirubin

Question 6

In the liver, _____ is conjugated into ______ by the liver enzyme named _______

Answer 6

Bilirubin, conjugated/direct bilirubin, Glucoronyl Transferase

Question 7

Conjugated bilirubin is:
water (soluble/insoluble)
(toxic/non-toxic) to cells
(passable/too large to pass) glomerular BM

Answer 7

relatively water soluble
non-toxic
passable

Question 8

Conjugated bilirubin spills into bloodstream only when

Answer 8

there is injury of the liver cells, which interferes with transfer of bilirubin to bile canaliculi

Question 9

You see conjugated bilirubin in the plasma =

Answer 9

Liver Cell Damage! Arg!

Question 10

What kind of bilirubin is found in the urine?

Answer 10

ONLY conjugated!

Question 11

When will you see both conjugated and unconjugated bilirubin in the plasma?

Answer 11

massive hemolysis

Question 12

In the intestines, bilirubin is reduced by bacteria to ________

Answer 12

urobilinogen (UBG)

Question 13

How much urobilinogen is absorbed from the colon and returned to the liver and re-excreted by liver cells into bile?

Answer 13

20%

Question 14

How much of the urobilinogen is reabsorbed and remains in the plasma and is excreted in the urine?

Answer 14

A small fraction

Question 15

What are the two tests for Lab analysis of bilirubin?

Answer 15

Total bilirubin test: measures conjugated and unconjugated forms
Direct Bilirubin test: measures only conjugated

Question 16

How do you measure Unconjugated Bilirubin?

Answer 16

Total - Direct = Indirect = Unconjugated

Question 17

When would you use bilirubinometers?

Answer 17

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

Question 18

What are things than can screw with your billirubin specimen collection?

Answer 18

Hemolysis causes falsely decreased results
Want to get a fasting so it is free of lipemia
Light causes falsely decreased results

Question 19

Causes of hyperbilirubinemia

Answer 19

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

Question 20

Inc. in plasma unconjugated bilirubin

Answer 20

Hemolytic disease, Genetic errors (Gilbert’s syndrome, grigler-naijar syndrome, lucey-driscoll syndrome) Physiologic jaundice of newborn, ineffective erythropoiesis, drugs competing for glucuronide

Question 21

Inc. in plasma conjugated billirubin

Answer 21

Cholestasis, genetic errors, biliary atresia, hepator cellular damage

Question 22

Prehepatic disease:

Answer 22

Inc. Unconjegated bili
Normal Conjugated bili
Inc. Urine UBG
NO Urine bilirubin

Question 23

Posthepatic disease

Answer 23

Inc. Conjugated bili
Normal Unconjugated bili
Inc Urine bilirubin
NO Urine UBG
FECES: Chalky white

Question 24

Hepatic disease (Post-conjugation transport defect)

Answer 24

Inc. Conjugated bili
Normal unconjugated bili
Inc Urine bilirubin
Urine UBG normal or increased?

Question 25

Hepatic disease (Bilirubin conjugation failure)

Answer 25

Inc. Unconjugated bili
Normal Conjugated
Neg. urine results
Chalky white feces

Question 26

Aminotransferases

Answer 26

AST=SGOT and ALT=SGPT

Question 27

1. AST measurement:

2. ALT measurement:

Answer 27

1. MI, hepatocellular disorders, skeletal muscle involvement

2. hepatic disorders only

Question 28

5 isoenzymes of LD that have tissue specificity

Answer 28

LD-1 and 2 - Heart, RBC (renal cortex)
LD-3 - non-specific, lung, lymphocytes, spleen, pancreas
LD-4 and 5 - Liver, skeletal muscle