Liver Functions

Question 1

What are the four major biochemical functions of the liver?

Answer 1

Excretion/secretion, metabolism, detoxification, storage

Question 2

What is the liver’s role in excretion?

Answer 2

Removes heme waste as bilirubin via bile

Question 3

What is bile made of? (3)

Answer 3

Bile acids/salts, bile pigments, cholesterol

Question 4

What key plasma proteins are made by the liver? (3)

Answer 4

Albumin, fibrinogen, clotting factors

Question 5

What vitamins does the liver store?

Answer 5

A, D, B12

Question 6

What mineral is stored in the liver?

Answer 6

Iron

Question 7

What does “first-pass metabolism” mean?

Answer 7

Substances from GI tract pass through liver before circulation

Question 8

What enzyme system detoxifies drugs in the liver?

Answer 8

Cytochrome P-450 (CYP450)

Question 9

Name two detoxification reactions used by the liver

Answer 9

Oxidation, reduction (also hydroxylation, demethylation)

Question 10

What is bilirubin?

Answer 10

A breakdown product of heme from RBCs

Question 11

Where are RBCs broken down?

Answer 11

Reticuloendothelial system

Question 12

What protein carries bilirubin in blood?

Answer 12

Albumin

Question 13

Is unconjugated bilirubin water soluble?

Answer 13

no

Question 14

Is conjugated bilirubin water soluble?

Answer 14

yes

Question 15

What pigment is formed first from heme?

Answer 15

Biliverdin

Question 16

What enzyme converts biliverdin to bilirubin?

Answer 16

Biliverdin reductase

Question 17

What enzyme conjugates bilirubin?

Answer 17

UDP-glucuronyl transferase

Question 17

Where does bilirubin conjugation occur? (cell name)

Answer 17

Hepatocytes

Question 18

What form is excreted into bile? (be spesific)

Answer 18

Bilirubin diglucuronide (conjugated)

Question 19

Another name for unconjugated bilirubin

Answer 19

Indirect bilirubin

Question 20

Another name for conjugated bilirubin

Answer 20

Direct bilirubin

Question 21

Which bilirubin reacts directly in diazo assays?

Answer 21

Conjugated bilirubin

Question 22

Which bilirubin requires an accelerator?

Answer 22

Unconjugated bilirubin

Question 23

Where is urobilinogen formed?

Answer 23

intestine

Question 24

What converts bilirubin to urobilinogen?

Answer 24

Anaerobic gut bacteria

Question 25

What gives stool its brown color?

Answer 25

stercobilin

Question 26

Where is most urobilinogen excreted?

Answer 26

Feces

Question 27

Where is a small amount of urobilinogen excreted?

Answer 27

urine

Question 28

what is jaundice?

Answer 28

Yellow discoloration due to ↑ bilirubin

Question 29

At what bilirubin level is jaundice visible?

Answer 29

~3–5 mg/dL

Question 30

Three categories of jaundice

Answer 30

Prehepatic, hepatic, posthepatic

Question 31

Primary cause of prehepatic jaundice

Answer 31

Increased RBC destruction

Question 32

Which bilirubin is increased in prehepatic jaundice?

Answer 32

Unconjugated

Question 33

Urine bilirubin in prehepatic jaundice?

Answer 33

Negative

Question 34

what causes hepatic jaundice?

Answer 34

Liver cell dysfunction

Question 35

Can both bilirubin forms be elevated?

Answer 35

yes

Question 36

Name one genetic cause of both forms of bilirubin being elevated

Answer 36

Gilbert’s syndrome

Question 37

Cause of posthepatic jaundice

Answer 37

Bile duct obstruction

Question 38

Which bilirubin increases most in post hepatic jaundice?

Answer 38

Conjugated

Question 39

Stool color in obstruction

Answer 39

Pale / clay-colored

Question 40

Main principle used to measure bilirubin

Answer 40

Diazo reaction

Question 41

What reagent reacts with bilirubin in the diazo rxn

Answer 41

Diazotized sulfanilic acid

Question 42

What color forms in the diazo reaction?

Answer 42

Azobilirubin

Question 43

What does color intensity reflect?

Answer 43

Bilirubin concentration

Question 44

Method that uses methanol as accelerator

Answer 44

Malloy–Evelyn

Question 45

Method of choice for bilirubin measurement

Answer 45

Jendrassik–Grof

Question 46

Accelerator used in Jendrassik–Grof

Answer 46

Caffeine–benzoate

Question 47

What destroys bilirubin in samples?

Answer 47

light

Question 48

Effect of hemolysis on bilirubin testing

Answer 48

Interference with reaction

Question 49

Why is lipemia a problem?

Answer 49

causes turbidity

Question 50

Method used to measure urobilinogen

Answer 50

Ehrlich aldehyde reaction

Question 51

Normal urine urobilinogen?

Answer 51

Small amount present

Question 52

Enzymes indicating hepatocellular injury

Answer 52

AST, ALT

Question 53

Enzymes indicating cholestasis

Answer 53

ALP, GGT

Question 54

Enzyme most associated with alcohol use

Answer 54

GGT

Question 55

Lab test reflecting protein synthesis

Answer 55

Albumin

Question 56

Lab test reflecting clotting factor synthesis

Answer 56

Prothrombin time (PT)

Question 57

Population most affected by Reye’s syndrome

Answer 57

Children

Question 58

key lab abnormality in Reye’s syndrome

Answer 58

Elevated ammonia