Liver Function and Cholestasis

The Hepatobiliary System

• The hepatobiliary system consists of the liver, gallbladder, and bile ducts.
• The liver has a dual blood supply, receiving blood from the hepatic artery and the portal vein.
• The lobules are the functional units of the liver.
• The portal circulation carries blood from the gastrointestinal tract, spleen, and pancreas to the liver before returning to the heart.

Functions of the Liver

• Metabolic functions include: • Carbohydrate metabolism (glycogenesis, glycogenolysis, and gluconeogenesis) • Conversion of ammonia to urea • Metabolism of drugs and hormones (steroids)
• The liver removes, conjugates, and secretes bilirubin into bile.
• The liver is responsible for protein synthesis, including the production of albumin and coagulation factors.
• The liver produces approximately 600-1200 mL of bile daily, which contains bile salts essential for digestion and absorption of fat-soluble vitamins.

Gastritis

• Gastritis is inflammation of the gastric mucosa, which can be acute or chronic.
• Acute gastritis is a transient inflammation associated with local irritants such as bacterial endotoxins, caffeine, alcohol, and aspirin.
• Chronic gastritis is characterized by the absence of grossly visible erosions, chronic inflammatory changes, and atrophy of the glandular epithelium of the stomach.

Cholestasis

• Cholestasis is a decrease in bile flow through the intrahepatic bile ducts, leading to destructive liver changes and an accumulation of bile components in the blood.
• Jaundice occurs when bilirubin accumulates in the blood due to excessive red blood cell destruction, failure of the liver to remove and conjugate bilirubin, or obstructed biliary flow.

Liver Failure

• Liver failure can result from sudden and massive hepatic destruction or progressive damage to the liver.
• At least 80-90% of hepatic functional capacity must be lost before hepatic failure occurs.
• Causes of liver failure include fulminant hepatitis, alcoholic cirrhosis, and cancer liver or extensive metastasis.

Hepatic Encephalopathy

• Hepatic encephalopathy refers to central nervous system manifestations of liver failure.
• It is characterized by neural disturbances ranging from a lack of mental alertness to confusion, coma, and convulsions.
• A very early sign of hepatic encephalopathy is a flapping tremor.
• It is due to the accumulation of neurotoxins (ammonia) in the blood because the liver has lost its detoxifying capacity.

This quiz covers the functions of the liver, including its role in excretion, and the concept of cholestasis, its effects on the liver, and its relationship to jaundice.