Bilirubin Pathways Flashcards Preview

Jason's GI Block > Bilirubin Pathways > Flashcards

Flashcards in Bilirubin Pathways Deck (46):
1

bilirubin is an open chain called?

a tetrapyrrole rings

2

bilirubin breakdown of blood usually where?

spleen

3

Macrophages break form RBCs, then what?

into haem>biliverdin>free bilirubin

4

colour of bilirubin?

yellow

5

colour of biliverdin?

green

6

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

exposed to light = more soluble

7

When use phototherapy for bilirubin?

jaundiced newborns

8

2 forms of bilirubin?

conjugated and unconjugated

9

bilirubin usually excreted as?

conjugated (glucuronide) in bile

10

high bilirubin in newborns?

neurotoxic

11

RBCs stimulated by?

EPO
erythropoietin

12

how many RBCs made a die per second?

2 million

13

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

reticulocytes mature in a day

14

how long to create RBCs from stems?

7 days

15

RBCs last?

~120 days

16

what is met-haemoglobin?

Fe3+ that doesn't bind O2 well

17

What is in white pulp and red pulp in spleen?

White pulp: T/B cells
Red pulp: blood vessels to remove old RBCs via macrophages

18

Mononuclear phagocyte is precursor to?

macrophage

19

Are there Mononuclear phagocytes in the liver?

yes. the Kupffer cells help out

20

what does the white pulp in spleen do?

opsonizes old RBCs to help with recognition by macrophages

21

aged RBCs lose what on their surface?

neuraminic/sialic acid from glycophorin

22

3 big factors for haemolysis?

strepto/enterococcus
parasitic: Malaria
congenital/genetic/autoimmune

23

What is Haptoglobin?

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

24

Haptoglobin looks like?

trypsin

25

what carried haem (not Haemoglobin) to liver?

hemopexin recycles the iron

26

4 consequences of haemolysis

unconjugated bilirubin = jaundice
increased stercobilin
gall stones
reticulocytosis

27

Fe2+ carried by?

transferrin

28

Haem oxygenase produces?

biliverdin

29

How is biliverdin produces from Haem?

via haem oxygenase

30

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

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

31

serum albumin binds what?

HIGHLY hydrophobic bilirubin

32

what converts bilirubin to conjugated bilirubin?

bilirubin UDP glucuronyltransferase

33

whats the difference between conjugated and unconjugated bilirubin?

conjugated is soluble

34

defect in bilirubin UDP glucuronyltransferase leads to what disease?

Crigler-Najjar disease

35

what actively pumps bilirubin diglucuronide into canaliculi?

cMOAT or MRP2

36

what is Crigler-Najjar disease?

defect in bilirubin UDP glucuronyltransferase

37

What is Dubin Johnson syndrome? prognosis?

defect in cMOAT
asymptomatic, no Rx necessary

38

Crigler-Najjar disease symptoms?

persistent jaundice
kernicterus

39

What is kernicterus?

bilirubin in brain

40

Crigler-Najjar disease initial and subsequent treatment?

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

41

How much bile is recycled?

95% in terminal ileum

42

what are bile pigments?

bilirubin diglucuronide

43

what are bile salts?what do they do?

detergent derivatives of cholesterol
emulsify fats

44

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

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

45

Why does old pee look more yellow?

+++ oxidized urobilinogen

46

What converts bilirubin diglucoruronide to sterco and urobilinogen?

microbial enzymes