Liver Structure and Function

Question 1

3 cell types in liver

Answer 1

1. hepatocytes - 60%
2. cholangiocytes: intracellular channels -> bile canaliculi - 5% -
3. non-parenchymal cells: endothelial, Kupffer, hepatic stellate, pit cells - 35%

Question 2

function of Kupffer cells

Answer 2

macrophages, BM derived
phagocytosis of toxins, bacteria
secretion of inflammatory mediators

Question 3

function of sinusoidal endothelial cells

Answer 3

fenestrated structure –> rapid exchange b/t blood and sinusoid

Question 4

function of hepatic stellate cells

Answer 4

collagen synthesis

Question 5

where does the hepatic artery come from? go to? what does it supply?

Answer 5

celiac artery –> common hepatic –> left and right hepatic
OR
SMA –> right hepatic; left gastric –> left hepatic

Question 6

blood supply for gallbladder

Answer 6

one or two cystic arteries from R. Hepatic

Question 7

outflow from liver

Answer 7

hepatic veins: left, middle, right

usually mid and left join b/f entering vena cava

Question 8

portal vein function

Answer 8

inflow: delivers 705 of total liver blood flow from intestine
splenic vein + SMV –> portal vein

Question 9

where does lymph form in the liver?

Answer 9

space of Disse

Portal tracts, around hepatic veins

Question 10

where does lymph go from the liver?

Answer 10

there are lymphatic vessels in small portal tracts and walls of small hepatic veins
- drain to lymph nodes of hilum and caval vein

Question 11

nerve supply of the liver

Answer 11

symp and parasympathetic: lower thoracic ganglia, celiac plexus, vagus nerve, right phrenic nerve

Question 12

what keeps the liver in place?

Answer 12

coronary ligaments
right and left triangular ligaments
falciform ligament: contains round ligament
hepatoduodenal ligament (teres hepatis)

Question 13

round ligament develops from…

Answer 13

obliterated umbilical vein

Question 14

contents of the hepatoduodenal ligament

Answer 14

hepatic artery
portal vein
common bile duct
lymphatic vessels
nerves

Question 15

describe the different surfaces of hepatocytes

Answer 15

basal: faces sinusoidal space, microvilli
apical: faces adjacent cells, enclose bile canaliculi
lateral: forms bile canaliculi and Disse’s space

Question 16

steps of bilirubin production and excretion

Answer 16

production: breakdown RBCs: Hgb –> heme –> biliverdin –> bilirubin
excretion: unconj (lipid soluble)bili transported in blood bound to albumin –> bill taken up by hepatocytes –> bound to glutathione-s-transferase –> conj by bill UDP-glucoronosyltransferase –> conj bill (water soluble) transported to bile ducts + some enters back into blood stream

Question 17

what is bile made of?

Answer 17

conj bili
cholesterol, phospholipids
bile salts
water, electrolytes

Question 18

causes of hyperbilirubinemia - unconj

Answer 18

increased production (hemolysis)
liver cell damage (no uptake)
decreased conjugation (limited UDP-glucuronosyltransferase): congenital causes like Gilbert's or acquired drug effect

Question 19

causes of hyperbilirubinemia - conj

Answer 19

liver cell damage (limited MRP2 activity)
OBSTRUCTION - stone or tumor
decreased excretion (limited MRP2 activity): congenital causes = Dubin-Johnson, Rotor

Question 20

how does detox of exogenous toxins and drugs work?

Answer 20

Phase I: CYP450 system

Phase III: other stuff incl. glucuronidation, sulfation, methylation, more

Question 21

liver metabolism of carbs

Answer 21

glycogen storage, gluconeogenesis

G-6-P is important branch point molecule

Question 22

carbs other than glucose in the liver

Answer 22

fructose, hepatic glycogen, lactate, alanine

Question 23

elevated AST and ALT

Answer 23

parenchymal injury - hepatitis

Question 24

elevated AP + gamma-GT

Answer 24

biliary tract injury - cholestatic