Liver Flashcards
What bilirubin (conjugated/unconjugated) is measured in the direct bilirubin?
Direct bilirubin = conjugated
(Van den Berg reaction - direct = conjugated then something is added that measures total)
Toal- direct = indirect= unconjugated
How does Phototherpy as treatment for neonatal jaundice work?
Converts bilirubin into two other compounds, lumirubin and photobilirubin which are isomers that do not need conjugation for excretion.
What is the pathophystiology of Gilbert’s ?
UDP glucuronyl transferase activity reduced to 30%
–> decreased bilirubin (worse with fasting, stress etc.)
Explain Hepatitis B serology
What makers?
What do they indicate?
What are histologically defining features of alcoholic hepatitis?
- Ballooning degeneration +/-
- Mallory-Denk Bodies (marker of chronic hepatitis (hyaline inclusion in hepatocytic cytoplasim)
inflammation
fibrosis
What nutritinal deficiency causes Beri-Beri?
B1 deficiency
At what sites does porto-systemic anastomosis occur?
Oesophageal varices
Rectal varices
Umbilical vein recanalising
Spleno-renal shunt
What is Courvoisier’s law?
In the presence of jaundice, if the gall bladder is palpable, the cause is unlikely to be gall stones.
This is because a gall bladder with stones is usually small and fibrotic and incapable of being large.
What are the components of the hepatic lobule?
How does it grossly work?
Hepatic lobule = hexagonal functional structure of the liver
- Hepatic vein at center (central vein)
- Blood enters via the portal Vein in the Portal tracts, that contrain 3 structures (portal triad) (bile, vein, artrey)
- Goes through 3 zones:
Zone1: closest to portal triad
Zone 2 in between
Zone 3: closest to central vein
Where is Zone 1in the hepatic lobule located?
In what pathology does it get affected first?
Zone 1 = closest to portal triad: most oxygen
–> Blood flow and filtration from portal triad to central vein, bile flow in opposite direction
But also first affected in viral hepatitis
What is the main function of hepatocytes in Zone 3?
When do they experience damage?
The least oxygenated zone, and thus most susceptible to ischemia
Most sensitive to metabolic toxins as this is the most metabolically active (e.g., ethanol, CCl4, halothane, rifampin, acetaminophen)
Has the highest amount of cytochrome P-450 –> most liver metabolism happens here
How much bile is produced every day?
600-1000ml
What is the perisinusoidal space in the liver called?
What lie quiescently in that space and what is their function?
- space (of Disse): contains hepatic stellate cells
- store vitamin A
- extracellular matrix production in liver injury (formation of scar tissue → fibrosis)
What are histological finsinds of acutet hepatitis?
Caused bei either viruses (Hep A-E) or Drugs
Histopathology shows spottynecrosis (small foci of inflammatiton and infiltrates)
What is the normal weight of the liver?
1500g
What is the blood suppy of the liver?
Dual blood supply –> makes ischaemia unlikey
- Portal vein
- hepatic artery
What is a hepatic acinus?
Devision of the liver lobule considering blood flow, intorhobus shaped devisins
What is the function of liver Kupffer cells?
Where are they located?
Kupffer cells (a type of macrophage) are housed in the sinusoids
These cells phagocytize foreign particles, bacteria, and damaged, old blood cells.
What are hepatic stellate cells?
What is their main function?
Usually: store Vitamin A
Otherwise
Can get activated –> become myofibroblast –> and are the main source of extracellular matrix production in liver injury (formation of scar tissue → fibrosis)
What are the histological changes in Liver injuries?
- Loss of hepatocyte microvilli
- acvication of stellate cells –> deposition of scar tissue
- Loss of fenestration in endothelial cells
- Kupffer cell activation
What is the definition of cirrhosis?
Structural and functional abnromalities
- Whole liver involved
- Fibrosis (blue)
- Nodules of regenerating hepatocytes (centre of picture)
Leading to:
Functionally
Distortion of liver vascular architecture (obstruction of blood flow) –> inra- and extra-hepatic shunting of blood (no filtration of blood)
–> no blood to hepatocytes
How can liver cirrhosis be classified?
- Nodule size (micronodular vs macronodular) –> not super useful
- Aetiology of cirrhosis –> useful
What are the main complicatios of cirrhosis?
- Portal HTN
- Hepatic encephalopathy
- Hepatocellular carcinoma
Is cirrhosis reversible?
It sometimes can be
(e.g. with good treatment of viral hepatitis)