Liver Development, Anatomy

Question 1

Majority of blood supply to the liver is delivered via?

Answer 1

Portal Vein (75%)
(Hepatic artery 25%)

Question 2

What are the macrophages within the liver called?

Answer 2

Kuppfer Cells

Question 3

Which cells store Vitamin A and Lipids?

Answer 3

Ito cells

Question 4

Which embryonic structure fuses with the vitelline vein to become the portal vein?

Answer 4

Right umbilical vein

Question 5

Ischemia to a liver lobule would first present in which zone?

Answer 5

Medial Zone

i.e. zone 3

Question 6

During development, the pancreas is located in which layer of mesentery?

Answer 6

Dorsal mesentery

Question 7

During development, the liver is located in which layer of mesentery?

Answer 7

Ventral mesentery

nb: liver growth destroys ventral mesentery

Question 8

Which two ligaments are contained in the lesser omentum?

Answer 8

Hepatogastric Ligament

Hepatoduodenal Ligament

Question 9

Bile acid that is produced in the liver is ultimately reabsorbed in which structure?

Answer 9

Terminal Ileum

Question 10

What is the rate limiting step in the production of bile acids?

Answer 10

Conversion of Cholesterol via CYP7A1 to chenodoxycholic acid (CDA) or cholic acid (CA)
Ratio CDA 1:3 CA

Question 11

Secondary bile acids consist of _______ and ________ and are produced by _________.

Answer 11

Deoxycholic acid and Lithocholic acid via bacteria

Question 12

Bile acids are conjugated in which organ?

Answer 12

Liver

Question 13

Bile acids are conjugated to what amino acids?

Answer 13

Taurine and Glycine

Question 14

Properties of conjugated bile acids?

Answer 14

Increased solubility of bile acids at luminal pH
Resistant to precipitation by Ca2+ and H+
Prevents passive reabsorption

Question 15

Formation of mixed micelle requires the proper ratio of which 3 components?

Answer 15

Cholesterol (1.0), Bile Acids (0.3), Phosphotidylcholine(0.1)

Question 16

What properties of a mixed micelle leads to increase risk of cholesterol gall stones?

Answer 16

Increased Cholesterol

Decreased Bile Acids

Question 17

What are the major secretory cells in the biliary system?

Answer 17

Cholangiocytes

Question 18

Properties of cholangiocytes

Answer 18

Use CFTR to secrete HCO3- and Cl-
Regulated via Secretin in ACh manner
Absorbs glucose
Injury to ductal system results in increase in GGT marker

Question 19

Mechanism for down regulating production of CYP7A1

Answer 19

CDCA binds to FXR in enterocytes producing FGF-19
FGF-19 enters portal circulation and binds to FGF-R in hepatocytes
Binding of FGF-R to FGF-19 downregulates CYP7A1

Question 20

What is the nature of unconjugated bilirubin?

Answer 20

Unconjugated bilirubin is bound to albumin

Question 21

What is the nature of conjugated bilirubin and what enzyme facilitates conjugated bilirubin?

Answer 21

Conjugated bilirubin is bound to glucouronic acid

UGT facilitates binding of bilirubin to glucouronic acid

Question 22

What are the properties of conjugated bilirubin?

Answer 22

More soluble
secreted for excretion
NOT reabsorbed in the intestines

Question 23

What can occur in the colon to conjugated bilirubin?

Answer 23

Bacteria can deconjugate bilirubin into Urobilinogen

UroB can be reabsorbed by liver or excreted in urine and stool

Question 24

How is bilirubin conjugated?

Answer 24

Bilirubin is conjugated to glucouronic acid via UGT