Bilirubin Metabolism

Question 1

Bilirubin is a by product of what?

Answer 1

Red blood cell breakdown in the spleen

Question 2

Old red blood cells >? days are broken down to release what two things?

Answer 2

120

Heme and globin

Question 3

The heme is further broken down the release what?

Answer 3

Iron and biliverdin

Question 4

Biliverdin is converted into what? How is it carried in the blood?

Answer 4

Bilirubin

Attached to albumin

Question 5

Bilirubin attached to albumin is insoluble to what? Soluble in what?

Answer 5

Water (indirect) - insoluble

Lipids - soluble

Question 6

The Bilirubin is transported to the liver where it is conjugated with a __________ by _______?

Answer 6

glucuronide

UDPG transferase

Question 7

Conjugation of the Bilirubin does what to it?

Answer 7

Renders it into a water-soluble state

Question 8

Conjugated (direct) bilirubin is secreted into what and stored where?

Answer 8

biliary tract

gallbladder

Question 9

Bile is bilirubin plus what?

Answer 9

Bile salts

Question 10

Bile does what to fat?

Answer 10

saponifies it (like soap) rendering it more easily digested by pancreatic lipase

Question 11

The bilirubin in the gut is converted to what by bacteria?

Answer 11

urobilinogen

Question 12

What happens to 90% of the urobilinogen?

Answer 12

Absorbed into the blood stream

Question 13

5% of the urobilinogen does what?

Answer 13

Is excreted in the urine where it is covered to urobilin

Question 14

What colors the urine yellow?

Answer 14

urobilin

Question 15

10% of the urobilinogen in the gut is converted into what?

Answer 15

stercobilinogen

Question 16

Stercobilinogen is oxidized into what?

Answer 16

Stercobilin

Question 17

What colors the stool brown?

Answer 17

stercobilin

Question 18

What percentage of the bile salts are reabsorbed and sent back to the liver (enterohepatic circulation)?

Answer 18

95%