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1st Year - Gastroenterology > LFTs > Flashcards

Flashcards in LFTs Deck (49)
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1

What is bilirubin formed from?

Breakdown of RBC porphyrin ring

2

What organ does insoluble unconjugated iron travel to?

Liver

3

How does insoluble unconjugated iron travel to the liver?

Bound to albumin

4

What happen to insoluble unconjugated bilirubin at the liver?

Liver enzymes conjugated it to form bilirubin glucuronide (conjugated bilirubin)

5

How is conjugated bilirubin excreted?

In bile = soluble

6

How can conjugated bilirubin be excreted directly?

In urine

7

What happens to conjugated bilirubin in bile?

It is broken down in the gut into urobilinogen (some reabsorbed and excreted by the kidney) and stercobilinogen (forms brown colour of stool)

8

What sign can increase bilirubin cause?

Jaundice

9

At what level of bilirubin would jaundice be visible?

>35 micro mol/L

10

What are the 4 liver enzymes?

Alanine transaminase (ALT)
Aspartase transaminase (AST)
Alkaline phosphate (ALP)
Gama glutanyl transferase (GGT)

11

What are the 3 intracellular liver enzymes?

ALT
AST
ALP

12

What happens to ALT when liver cells damaged?

Release from liver into blood stream

13

Is ALT specific?

Yes, found almost exclusively in the liver

14

Is AST specific?

Not as much as ALT - also found in cardiac tissue and muscle

15

What happens to AST when liver cells damaged?

Released from liver into blood stream

16

Where is ALP found?

Mainly in liver and bone

17

What is the function of ALP?

Involved in transport of substances across the cell membrane

18

Why might ALP be raised?

Physiologically - metabolically active cells e.g. bones growing, pregnant
Bile drainage obstructed

19

Where is ALP found in the liver?

In cells near the bile ducts sad canaliculae

20

Where is GGT found in the liver?

In hepatocytes and biliary epithelial cells

21

What is the purpose of GGT?

Plays a role in the metabolism of drugs

22

Name 2 conditions which cause a rise in GGT?

Alcohol and certain drugs
Bile duct obsturction

23

Where is albumin synthesised?

Liver

24

What happens to albumin levels as liver function deteriorates?

Falls

25

Apart from liver function, name 3 other causes of low albumin levels?

Protienuria
Poor nutrition
Hormonal imbalances

26

What happens to prothrombin time if liver problem?

Increases

27

What causes pre-hepatic jaundice?

Increased breakdown of RBCs

28

What causes intra-hepatic jaundice?

Problem in the liver

29

What causes post-hepatic jaundice?

Bile duct system damaged/ obstructed = unable to move bile into digestive tract

30

Bilirubin in prehepatic jaundice?

Raised

31

AST/ ALT in prehepatic jaundice?

Normal

32

ALP in prehepatic jaundice?

Normal

33

Haemoglobin in prehepatic jaundice?

Reduced

34

Jaundice in prehepatic jaundice?

Usually mild

35

Urine in prehepatic jaundice?

Not dark

36

Bilirubin in intrahepatic jaundice?

Raised

37

AST/ ALT in intrahepatic jaundice?

Raised

38

ALP in intrahepatic jaudnice?

Slightly raised

39

Hb in intrahepatic jaundice?

Normal

40

Jaundice in intrahepatic jaudnice?

May be marked

41

Other name for post hepatic jaundice?

Cholestatic

42

Bilirubin in posthepatic jaundice?

Raised

43

AST/ ALT in posthepatic jaundice?

slightly raised

44

ALP in posthepatic jaundice?

very raised

45

Hb in posthepatic jaudnice?

Normal

46

Jaundice in posthepatic jaundice?

May be marked

47

Stool in posthepatic jaudnice?

Pale

48

What effect on stool does bilirubin have?

Make it darker -> pale stool = lack of bilirubin in GI tract

49

What effect does bilirubin have on urine?

Makes it darker -> if cholestatic jaundice, urine may be darker as bilirubin can't be excreted in stool (=light stool, dark urine)

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