Liver Physiology Flashcards
Which zone of the liver is closest to the porta hepatis
Zone 1 (therefore Zone 3 closest to hepatic vein)
What connects portal vein to the hepatic vein
Sinusoids
What causes cirrhosis
Any toxin eg alcohol, Hep B virus, autoimmune
Cirrhosis characterised by
Parenchymal nodules (fibrotic hepatocytes)
Cirrhosis impact on vascular architecture
Pressure build up (= shunts = varices), can eventually result in portal system flowing in reverse direction
Most common cause of portal hypertension
Intrahepatic from cirrhosis
Ascites
Accumulation of fluid in the abdomen = swelling
Impact of portal hypertension on brain
High ammonia in blood = hepatic encephalopathy
Places where blood goes when portal hypertension redirects
Spleen = splenomegaly
Oesophagus = varices
Anus = haemorrhoids
Umbilicus = Carpa medusa
Hepatitis A severity
Benign, cold-like, doesnt cause cirrhosis
Is hepatitis a synonym of cirrhosis
Chronic hepatitis CAN lead to cirrhosis, but not always
Hepatitis B severity
In most cases subclinical/acute
BUT when chronic = high rate of death, and since very common disease, still many deaths even though most nerve become chronic
Hepatitis C severity
Uncommon but very high percentage becomes chronic = fatal
Type of cancer Hep B/ Hep C can lead to
Hepatocellular carcinoma
What is a predictable hepatotoxin
We know it will cause harm to the liver (eg paracetamol) but the benefit outweighs the harm, when given in right dosage
Even if a chemical isn’t directly hepatotoxic, how can it still cause liver harm
Liver metabolically converts to an active toxin
Most common cause of acute liver failure
Paracetamol
Most common cause of chronic liver failure
Alcohol
Acute alcoholic liver disease results in
Hepatitis (-> cirrhosis if repeated attacks)
Chronic alcoholic liver disease results in
Steatosis (-> cirrhosis if continued exposure)
Steatosis
Fatty liver
How does alcohol result in Steatosis
Chnages in lipid metabolism
Non-alcoholic fatty liver disease causes
Obesity, diabetes, hypertension etc
Haemachromatosis
Excessive iron in liver
WHo gets haemochromatosis
People with genetic defect (everyone else excretes excess iron)
