7. Bile and Jaundice

Question 1

What hormone regulates the release of bile?

Answer 1

Cholecystokinin

Question 2

Is bile in the liver or bile in the gall bladder more concentrated?

Answer 2

Gall bladder

Question 3

What are some of the substances excreted by bile?

Answer 3

Bile pigments (degradation of haem)
Cholesterol
Bile acids/salts
Drugs and metabolites

Question 4

How does bile carry out digestion?

Answer 4

Bicarbonate neutralises acidity of gastric content
Bile salts and phospholipids emulsify fats
Activates pancreatic hydrolase precursors

Question 5

What is cholesterol broken down into in the liver?

Answer 5

Cholic acid

Chenodeoxycholic acid

Question 6

What are primary bile acids conjugated with?

Answer 6

Glycine

Taurine

Question 7

What are the secondary bile acids?

Answer 7

Deoxycholic acid

Lithocholic acid

Question 8

What is bilirubin?

Answer 8

Natural degradation product of haem

Question 9

What is the function of haptoglobin?

Answer 9

Forms a haemoglobin-haptoglobin complex

Prevents loss of iron in the urine

Question 10

What is the function of haemopexin?

Answer 10

Binds free haem

Iron is stored bound to ferrin

Question 11

What urobilinogen is excreted in the urine?

Answer 11

Urobilin

Question 12

What urobilinogen is excreted in faeces?

Answer 12

Stercobilin

Question 13

What is the name of the intermediate product from the breakdown of haem?

Answer 13

Biliverdin

Question 14

What cytoplasmic proteins does bilirubin bind to to prevent transport back out of the liver?

Answer 14

Glutathione S-transferases

Protein Y

Question 15

What de-conjugates bilirubin in the intestine?

Answer 15

Glucoronidases

Question 16

What is jaundice?

Answer 16

Yellow discolouration of the skin and sclera due to hyperbilirubinaemia

Question 17

What are the 3 types of jaundice?

Answer 17

Pre-hepatic
Intra-hepatic
Post-hepatic

Question 18

What is pre-hepatic jaundice?

Answer 18

Bilirubin production exceeds uptake capacity of liver

Question 19

What is intra-hepatic jaundice?

Answer 19

Bilirubin cannot be taken up, conjugated and/or secreted because hepatocytes are somehow damaged

Question 20

What is post-hepatic jaundice?

Answer 20

Obstruction to biliary flow

Question 21

What are other names for pre-hepatic jaundice?

Answer 21

Haemolytic

Hematogenous

Question 22

What are common causes of of pre-hepatic jaundice?

Answer 22

Haemolytic disease of newborn
Sickle cell disease
Autoimmune disease

Question 23

How is pre-hepatic jaundice diagnosed?

Answer 23

High plasma levels of uconjugated bilirubin

Question 24

What are other names for intra-hepatic jaundice?

Answer 24

Hepatic

Hepatocellular

Question 25

How is intra-hepatic jaundice diagnosed?

Answer 25

Hyperbilirubinaemia | Combined with elevated AST and ALT

Question 26

What are other names for post-hepatic jaundice?

Answer 26

Obstructive | Cholestatic

Question 27

How is post-hepatic jaundice diagnosed?

Answer 27

Pale stools Dark urine Urobilin may be absent from urine

Question 28

What are the causes of newborn jaundice?

Answer 28

Immature or impaired hepatic uptake or conjugation of bilirubin Red blood cell destruction

Question 29

What is kernicterus?

Answer 29

A rare form of brain damage caused by unconjugated bilirubin deposited in the brain

Question 30

How is newborn jaundice treated?

Answer 30

Phototherapy converts bilirubin to a water soluble non-toxic form Exchange blood transfusion to remove excess bilirubin Maternal phenobarbitone

Question 31

What is Gilbert's syndrome?

Answer 31

Mild, fluctuating hyperbilirubinaemia | Caused by reduced UDP-glucuronyl transferase or a defect in blirubin uptake

Question 32

How is Gilbert's syndrome treated?

Answer 32

Small doses of phenobarbitone | Stimulates UDP-glycuronyl transferase activity

Question 33

What is Crigler-Najjar syndrome?

Answer 33

Autosomal recessive disorder | Severe unconjugated hyperbilirubinaemia

Question 34

What is the cause of Crigler-Najar syndrome?

Answer 34

Mutation in the gene coding for UDP-glucuronyl transferase

Question 35

What is the treatment for type one Crigler-Najar syndrome (complete absence of enzyme)?

Answer 35

Liver transplant by age 5

Question 36

What is the treatment for type two Crigler-Najar syndrome (reduction in enzyme activity)?

Answer 36

Phenobarbitone | Phototherapy

Question 37

What are Dubin-Johnson and Rotor's syndromes?

Answer 37

Autosomal recessive disorders Conjugated hyperbilirubinaemia Impaired biliary secretion of conjugated bilirubin

Question 38

What is Dubin-Johnson syndrome caused by?

Answer 38

Mutation in the gene coding for MRP-2