Liver Pathology Flashcards
What are the major lifestyle contributors to liver disease?
Alcohol and obesity.
How is alcohol broken down in the liver?
Alcohol -> Acetaldehyde by alcohol dehydrogenase
Acetaldehyde is toxic -> Acetate by acetate dehydrogenase.
How does alcohol affect the liver?
Insufficient breakdown of alcohol into acetate results in accumulation of the toxic metabolic product Acetaldehyde. This causes increased levels of LDL in the liver, inflammation of the liver that causes damage and scar tissue to form and portal hypertension to occur.
What are the common causes of hepatic pathology?
Alcohol
Fatty liver disease
Hepatitis C and B
Biliary cirrhosis
What are the stages of alcohol damage in the liver?
Stage 1 is fatty alcoholic where increased accumulation of LDL causes the liver to be enlarged; this is reversible.
Stage 2 is chronic hepatitis where Acetaldehyde causes recruitment of macrophages and generation of radical oxygen species. This leads to hepatic jaundice, fever and an enlarged liver.
Stage 3 is Cirrhosis, which is irreversible damage that causes scar tissue formation.
What are the effects of portal hypertension?
Toxic products of metabolism aren’t cleared by the liver, and travel to the brain and cause neurological damage, leading to confusion, drowsiness and tremor.
What are the risk factors for alcoholic liver disease?
Women
Daily drinking > Binge drinking
Genetics
Lifestyle, with spirits being worst.
How does obesity affect the liver?
Insulin resistance causes high levels of circulating blood glucose which is taken up by the liver for storage into fat. Hypertension and hyper lipidaeimia contribute to accumulation of fat cells in the liver which impair function and result in liver cirrhosis. It begins with:
Non-alcoholic fatty liver with pain in the upper right abdomen which progresses to
Non-alcoholic steatohepatitis which is when fat cells accumulate enough to cause inflammation and jaundice.
Liver cirrhosis is the final irreversible stage.
What is the composition of the liver?
Liver is composed of cuboidal hepatocytes that have bile canaliculi between them, with blood supply from the hepatic artery and hepatic portal vein, where blood supply from the digestive system enters. This enters through the sinusoid which is lined with endothelial cells containing Kuppfer cells.
Large molecules such as protein move out through the porous gaps and gases move out into the Space of Disse, allowing nutrients to be taken up by hepatocytes.
What are Kuppfer cells?
Liver macrophages found on endothelial cells which line the sinusoids.
What are the hepatic stellate cells (HSC)?
Present in the sinusoid which activated when liver injury occurs, induce collagen production from hepatocytes that leads to liver fibrosis. When quiescent, they store vitamin A.
What are sinusoids?
Blood vessel which receives supply from branches of the hepatic artery and hepatic portal vein. It is lined with endothelial cells that contain Kuppfer macrophages for immune defences. Hepatocytes lie in close contact for uptake of nutrients.
What are the features of endothelial cells in the liver?
Highly leaky and porous, which lack a basement membrane and contribute to maintaining low pressure in the liver during digestion.
What is the Space of disse?
Area for the reversible flow of nutrients between the sinusoids and the hepatocytes.
What is the portal tract?
AKA portal triad hoc contains the hepatic artery, hepatic vein and bile duct.
What is the acinus?
Functional unit for blood flow in the liver.
What is the structure of a liver lobule?
Consists of a central vein with hepatocytes in rows, separated by sinusoids which receive blood from the portal tract.
Where does the central vein drain?
Inferior vena cava.
What is the exocrine function of the liver?
Produces bile, Along with bile acids and bile salts and albumin.
What are the endocrine function of the liver?
IGF-1
Plasma proteins and clotting factors like Angiotensinogen and Thrombopoetin
C
What separates the left and right lobes of the liver?
Falciform ligament, located anteriorly. It splits into the coronary ligaments.
What is the bare area?
Region in the liver not covered by peritoneum, where it is in contact with the diaphragm.
Which ligaments demarcate the bare area?
Coronary ligaments which posteriorly, form the left and right triangular ligaments.
Where do the ligaments connecting the liver to the organs originate?
From the porta hepatis. These include:
Hepatoduodenal ligmaent
Hepatogastric ligament: to lesser stomach curvature
Hepatorenal ligament
What connects the liver to the anterior abdominal wall?
Falciform ligament.
What is the major blood supply to the liver?
Hepatic portal vein, which is nutrient rich and contains drugs, but is oxygen poor.
What provides oxygenated blood to the liver?
Hepatic artery, a branch of the aorta. Majority is from the right hepatic artery
What is the round ligament?
Embryological remnant of the umbilical vein on the free edge of the Falciform ligament that develops 2 months post birth.
What are the hepatic veins of the liver?
They drain the liver into the inferior vena cava.
Upper group arise from the posterior aspect of liver to drain the caudate and left lobe.
Lower group arise from the right and quadrate lobe.
Where dot eh quadrate and caudate lobes arise?
From the right lobe of the liver.