Drive - bilirubin and haemoglobin

Question 1

What are bile pigments formed from?

Answer 1

The haem portion of broken down erythrocytes

Question 2

Where are old/damaged erythrocytes broken down?

Answer 2

The spleen, bone marrow and liver

Question 3

Describe the role of hemoxygenase (enzyme):

Answer 3

To breakdown the haem group into biliverdin, Fe2+ and CO

Question 4

Describe the role of biliverdin reductase:

Answer 4

Reduce biliverdin to the unconjugated

Question 5

Name 2 key properties of unconjugated bilirubin:

Answer 5

Toxic

Lipid soluble (therefore insoluble in the blood)

Question 6

How is unconjugated bilirubin converted to conjugated bilirubin?

Answer 6

In glucuronidation under the action of the enzyme UDP Glucuronyl Transferase

Question 7

What form of bilirubin can be found in bile?

Answer 7

Conjugated bilirubin

Question 8

What does reduction (hydrolysis) by intestinal bacteria cause the conversion of?

Answer 8

Conjugated bilirubin to be converted into urobilinogen

Question 9

What % of urobilinogen is reabsorbed into the blood?

Answer 9

10%

Question 10

What happens to the urobilinogen that is reabsorbed back into the blood?

Answer 10

Bound to albumin and transported to the liver where it is oxidised to urobilin

Question 11

What happens to urobilin?

Answer 11

Either re-cycled into bile or excreted in urine

Question 12

What does urobilin in urine do?

Answer 12

Gives urine its yellowish colour

Question 13

What happens to the 90% of urobilinogen that is not reabsorbed into the blood

Answer 13

It is oxidised by different intestinal bacteria to form stercobilin

Question 14

What happens to stercobilin?

Answer 14

It is excreted in faeces (responsible for the brownish colour)

Question 15

What cause jaundice?

Answer 15

High serum bilirubin levels.

Question 16

What are the 3 main types of jaundice?

Answer 16

Pre-hepatic
Hepatic
Post-hepatic

Question 17

What key levels are raised in pre-hepatic jaundice?

Answer 17

Increased serum unconjugated bilirubin

Without excess bilirubin in the urine

Question 18

What causes pre-hepatic jaundice (general)?

Answer 18

Increased breakdown of erythrocytes

Question 19

What causes hepatic jaundice (general)?

Answer 19

The cells of the liver are damaged so unable to metabolise the unconjugated bilirubin

Question 20

What key levels are raised in hepatic jaundice?

Answer 20

Increased serum unconjugated bilirubin

AND

Increased serum conjugated bilirubin

Question 21

What causes post-hepatic jaundice (general)?

Answer 21

When the biliary system is damaged, inflamed or obstructed

Question 22

What key levels are raised in post-hepatic jaundice?

Answer 22

Increased serum conjugated bilirubin

Question 23

What is a gall stone made from and how does it form?

Answer 23

Made from cholesterol.

Formed when cholesterol levels become high, the cholesterol will crystallise out of the solution (and form a gall stone)