Hepatobiliary and Pancreatic Disorders: Liver Structure and Functions

Structure of the Liver

• The liver is the largest gland in the body, divided into right and left lobes.
• 1500 mL of blood/min circulates through the liver and exits via the hepatic veins into the inferior vena cava.
• Bile is formed in the liver and exits through a system of ducts.

Physiology and Functions of the Liver

• The liver is integral to most body functions, performing over 500 tasks.
• The liver has the ability to regenerate, but only 10% to 20% of its function is needed to sustain life.

The Liver

• The right lobe is 6 times the size of the left lobe.
• Both lobes are made up of thousands of lobules connected to small ducts that form the hepatic duct.
• The hepatic duct transports bile produced by liver cells to the gallbladder and duodenum.
• The liver has two blood supplies: the hepatic artery, which provides oxygenated blood, and the hepatic portal vein, which provides nutrient-rich blood from the intestine.

Bile Production

• The liver produces bile, which is then stored in the gallbladder and transported to the duodenum through the biliary tract.
• Bilirubin is conjugated with glucoronic acid in the liver and then excreted in bile.
• Increased levels of bilirubin indicate liver disease.

Diseases of the Liver

• Acute viral hepatitis: widespread inflammation caused by viruses A, B, C, D, E, and G.
• Fulminant hepatitis: severe liver dysfunction accompanied by hepatic encephalopathy.
• Chronic hepatitis: lasting at least 6 months, caused by auto-immune, viral, metabolic, or medicine-induced factors.
• Non-alcoholic steatohepatitis (NASH): accumulation of fat droplets in hepatocytes leading to fibrosis and cirrhosis.
• Alcoholic liver disease: caused by alcohol metabolism, leading to fatty liver, alcoholic hepatitis, and cirrhosis.

Acute Viral Hepatitis

• Symptoms are divided into 4 phases: prodromal, preicteric, icteric, and convalescent.
• Viruses A and E are spread orally, while B, C, and D are spread through blood and body fluids.

Fulminant Hepatitis

• Defined by the absence of existing liver disease, with viral hepatitis accounting for 75% of cases.
• Complications include cerebral edema, coagulopathy, renal failure, and electrolyte imbalances.

Chronic Hepatitis

• Characterized by fatigue, sleep disturbances, difficulty concentrating, and right upper quadrant pain.
• Advanced disease is marked by jaundice, muscle wasting, edema, ascites, and encephalopathy.

Non-Alcoholic Fatty Liver Disease

• Accumulation of fat droplets in hepatocytes leads to fibrosis and cirrhosis.
• May be caused by inborn errors of metabolism, diabetes, obesity, or lipodystrophy.

Alcoholic Liver Disease

• Metabolism of alcohol leads to fatty acid accumulation, causing fatty liver and hyperlipidemia.
• Acetaldehyde causes cell membrane damage and necrosis.
• NADH replaces fatty acid as a fuel, promoting triglyceride accumulation.

Hepatic Encephalopathy

• Lactulose and rifaximin are used to treat encephalopathy by reducing ammonia production in the gut.
• Other hypotheses suggest the role of GABA receptors, altered neurotransmitters, and branched-chain amino acid imbalance in the development of encephalopathy.

Renal Insufficiency and Hepatorenal Syndrome

• Renal failure due to severe liver disease, characterized by low urine sodium levels.
• Treatment involves dextrose-based solutions, somatostatin, and H2 receptor antagonists.

Chronic Pancreatitis

• Recurrent attacks of epigastric pain, precipitated by meals, accompanied by nausea, vomiting, and diarrhea.
• Treatment involves avoiding large meals and alcohol, pancreatic enzyme replacement, and medium-chain triglycerides.

This quiz covers the structure and functions of the liver, including its physiology, blood circulation, and bile formation. Learn about the liver's vital roles in the body and its importance for survival.