Bilirubin Pathways

Question 1

bilirubin is an open chain called?

Answer 1

a tetrapyrrole rings

Question 2

bilirubin breakdown of blood usually where?

Answer 2

spleen

Question 3

Macrophages break form RBCs, then what?

Answer 3

into haem>biliverdin>free bilirubin

Question 4

colour of bilirubin?

Answer 4

yellow

Question 5

colour of biliverdin?

Answer 5

green

Question 6

some double bonds in bilirubin isomerize when what? what does that do to bilirubin?

Answer 6

exposed to light = more soluble

Question 7

When use phototherapy for bilirubin?

Answer 7

jaundiced newborns

Question 8

2 forms of bilirubin?

Answer 8

conjugated and unconjugated

Question 9

bilirubin usually excreted as?

Answer 9

conjugated (glucuronide) in bile

Question 10

high bilirubin in newborns?

Answer 10

neurotoxic

Question 11

RBCs stimulated by?

Answer 11

EPO

erythropoietin

Question 12

how many RBCs made a die per second?

Answer 12

2 million

Question 13

future RBCs leave the bone marrow as what? how long to mature to RBCs?

Answer 13

reticulocytes mature in a day

Question 14

how long to create RBCs from stems?

Answer 14

7 days

Question 15

RBCs last?

Answer 15

~120 days

Question 16

what is met-haemoglobin?

Answer 16

Fe3+ that doesn’t bind O2 well

Question 17

What is in white pulp and red pulp in spleen?

Answer 17

White pulp: T/B cells

Red pulp: blood vessels to remove old RBCs via macrophages

Question 18

Mononuclear phagocyte is precursor to?

Answer 18

macrophage

Question 19

Are there Mononuclear phagocytes in the liver?

Answer 19

yes. the Kupffer cells help out

Question 20

what does the white pulp in spleen do?

Answer 20

opsonizes old RBCs to help with recognition by macrophages

Question 21

aged RBCs lose what on their surface?

Answer 21

neuraminic/sialic acid from glycophorin

Question 22

3 big factors for haemolysis?

Answer 22

strepto/enterococcus
parasitic: Malaria
congenital/genetic/autoimmune

Question 23

What is Haptoglobin?

Answer 23

plasma protein that binds haemoglobin of RBCs that die away from spleen, allows macrophages to remove

Question 24

Haptoglobin looks like?

Answer 24

trypsin

Question 25

what carried haem (not Haemoglobin) to liver?

Answer 25

hemopexin recycles the iron

Question 26

4 consequences of haemolysis

Answer 26

unconjugated bilirubin = jaundice increased stercobilin gall stones reticulocytosis

Question 27

Fe2+ carried by?

Answer 27

transferrin

Question 28

Haem oxygenase produces?

Answer 28

biliverdin

Question 29

How is biliverdin produces from Haem?

Answer 29

via haem oxygenase

Question 30

``` Bruises: what happens at? 1-2 days 5-10 days 10-14 days >14 days ```

Answer 30

1-2 days: blue, purple black: deoxy/met-Hb 5-10 days: green/yellow = biliverdin 10-14 days: yellow/brown = bilirubin >14 days : fades away

Question 31

serum albumin binds what?

Answer 31

HIGHLY hydrophobic bilirubin

Question 32

what converts bilirubin to conjugated bilirubin?

Answer 32

bilirubin UDP glucuronyltransferase

Question 33

whats the difference between conjugated and unconjugated bilirubin?

Answer 33

conjugated is soluble

Question 34

defect in bilirubin UDP glucuronyltransferase leads to what disease?

Answer 34

Crigler-Najjar disease

Question 35

what actively pumps bilirubin diglucuronide into canaliculi?

Answer 35

cMOAT or MRP2

Question 36

what is Crigler-Najjar disease?

Answer 36

defect in bilirubin UDP glucuronyltransferase

Question 37

What is Dubin Johnson syndrome? prognosis?

Answer 37

defect in cMOAT | asymptomatic, no Rx necessary

Question 38

Crigler-Najjar disease symptoms?

Answer 38

persistent jaundice | kernicterus

Question 39

What is kernicterus?

Answer 39

bilirubin in brain

Question 40

Crigler-Najjar disease initial and subsequent treatment?

Answer 40

initially: phototherapy 10-12 hr/day subsequently: liver transplant

Question 41

How much bile is recycled?

Answer 41

95% in terminal ileum

Question 42

what are bile pigments?

Answer 42

bilirubin diglucuronide

Question 43

what are bile salts?what do they do?

Answer 43

detergent derivatives of cholesterol | emulsify fats

Question 44

90% of urobilinogen in faeces, 10% goes where?

Answer 44

10% back into portal vein 9% back to biliary system 1% into kidney and into urine = yellow pee

Question 45

Why does old pee look more yellow?

Answer 45

+++ oxidized urobilinogen

Question 46

What converts bilirubin diglucoruronide to sterco and urobilinogen?

Answer 46

microbial enzymes