Bilirubin (p. 384)

Question 1

By which enzyme is heme metabolized? What is it converted to? Where does this take place?

Answer 1

Heme is metabolized by heme oxygenase into biliverdin, which is further reduced to bilirubin.

This occurs in the bloodstream (macrophages).

Question 2

Bilirubin is a breakdown product of what?

Answer 2

Heme

Question 3

By which organ is unconjugated bilirubin removed from the blood?

Answer 3

Liver

Question 4

What does the liver do with unconjugated bilirubin?

Answer 4

Conjugate it with glucuronate and excrete in the bile

Question 5

What is bilirubin conjugated to?

Answer 5

glucuronate

Question 6

On which protein is unconjugated bilirubin transported to the liver?

Answer 6

Albumin

Question 7

Which enzyme conjugates unconjugated bilirubin to glucunorate in the liver?

Answer 7

UDP-glucuronosyl-transferase

Question 8

What is direct bilirubin?

Answer 8

bilirubin conjugated to glucunorate. water-soluble

Question 9

Is direct bilirubin water soluble?

Answer 9

yes

Question 10

what is indirect bilirubin?

Answer 10

unconjugated bilirubin. water insoluble

Question 11

is indirect bilirubin water soluble?

Answer 11

no

Question 12

what does conjugated bilirubin get converted into by gut bacteria?

Answer 12

urobilinogen

Question 13

what does convert conjugated bilirubin into urobilinogen inside the gut?

Answer 13

bacteria

Question 14

what percentage of urobilinogen gets excreted into the feces as stercobilin?

Answer 14

20%

Question 15

how do you call urobilinogen that gets excreted into the feces?

Answer 15

stercobilin

Question 16

what leads to the brown color of the stool?

Answer 16

stercobilin

Question 17

what percentage of urobilinogen goes back into the body? (not excreted by stool)

Answer 17

20% back into body

Question 18

20% of urobiligen goes back into the back (the rest gets excreted via stool)

what percentage of this goes to the kidney?

Answer 18

10%

Question 19

20% of urobiligen goes back into the back (the rest gets excreted via stool)

what percentage goes back into the enterohepatic circulation?

Answer 19

90%

Question 20

how does urobilinogen gets excreted in urine (how do you call it)?

Answer 20

urobilin

Question 21

what does urobilin do to the urine?

Answer 21

gives it the yellow color

Question 22

what gives the yellow color to urine?

Answer 22

urobilin