Hepatobiliary-Pancreatic System & Liver Anatomy

Hepatobiliary-Pancreatic system overview

• The hepatobiliary-pancreatic system includes the liver, biliary tract, and pancreas.

Hepatic system - Liver

• The liver weighs approximately 3 lbs (1.37 kg) in an adult.
• The liver is the largest organ in the body.
• The liver is located directly beneath the diaphragm at the right epigastric region.
• The falciform ligament divides the liver into two lobes, where the right lobe is larger.
• The liver can repair itself and regenerate damaged tissue to a certain extent.
• Hepatic sinusoids contain phagocytic cells to remove foreign particles from the blood.
• The central vein is at the center of each lobule.
• Mixed blood flows toward the central vein, forming hepatic veins.

Liver Ducts

• Hepatic ducts transport bile out of the liver.
• The common hepatic duct is formed from the left and right hepatic ducts.
• The cystic duct joins the common hepatic duct, and originates from the gallbladder.
• The common bile duct is formed from the common hepatic duct and cystic duct.

Major Functions of the Liver

• Metabolic functions include carbohydrate, protein, and fat metabolism, detoxification, and steroid metabolism.
• In carbohydrate metabolism, the liver converts amino acids and fatty acids to glucose through gluconeogenesis.
• Glycogenesis, or glycogen synthesis, is the conversion of glucose to glycogen.
• Glycogenolysis, or glycogen hydrolysis, is the process of breaking down glycogen into glucose.
• In protein metabolism, the liver converts NH3 ammonia to urea.
• In fat metabolism, the liver synthesizes fatty acids from amino acids and glucose.
• The liver breaks down triglycerides.
• Detoxification involves inactivation of drugs and harmful substances.
• Steroid metabolism involves excretion of gonadal and adrenal corticosteroid.
• Bile synthesis happens through bile production by hepatocytes.
• The liver excretes about 1 L of bile per day.
• Storage: The liver stores glucose in the form of glycogen, and Vitamins A, D, E, and K.
• Phagocytic system: The liver breaks down RBCs, WBCs, and bacteria.
• The liver breaks down hemoglobin to bilirubin.

Bilirubin Metabolism

• Bilirubin is a waste product of the breakdown of the hemoglobin molecule.
• Aged RBC-> Hemoglobin -> Heme and Globin
• Bilirubin (insoluble) -> Attached to albumin -> Unconjugated bilirubin (indirect bilirubin) - insoluble
• Liver -> Unconjugated bilirubin combines with glucuronic acid (glucuronide) -> Conjugated bilirubin (direct bilirubin) – soluble
• Excreted in the bile -> Intestine (bilirubin reduced to urobilinogen and stercobilinogen by intestinal bacteria)
• Stercobilinogen gives brown color to stool
• Urobilinogen goes in systemic circulation and excreted in urine

Bilirubin Disorders

• Jaundice is the yellow pigmentation of the skin and sclera.
• Icterus is the yellow coloration in the sclera of the eye.
• Kernicterus is excessive accumulation of bilirubin in the brain that causes brain damage.
• Crigler-Najjar disease is a recessive inherited disorder characterized by the inability to conjugate bilirubin.
• The Crigler-Najjar disease leads to severe neurological impairments, and these patients have a life expectancy of one year or less.

Biliary Tract

• The biliary tract is composed of the gallbladder, common bile duct, cystic duct, and hepatic duct that drain bile.
• The gallbladder is a pear-shaped sac located below the liver.
• The gallbladder concentrates and stores bile.
• It can hold approximately 40 – 70 ml of bile.

Pancreas

• The pancreas is a long, thin glandular organ essential for digestion and metabolism.
• There are two major cell types: Exocrine and Endocrine
• Exocrine cells
• Acini cells produce pancreatic enzymes.
• Endocrine cells - Islets of Langerhans.
• Alpha cells produce glucagon.
• Beta cells produce insulin.
• Delta cells produce somatostatin.

Diagnostic Tests

• Liver Function Tests (LFT) include Albumin, total and direct bilirubin, alkaline phosphatase, Aspartate Transaminase (AST) / Serum Glutamic-Oxaloacetic Transaminase (SGOT), and Alanine Aminotransferase (ALT) / Serum Glutamic Pyruvic Transaminase (SGPT).
• A Liver biopsy procures a small sample of liver tissue to diagnose liver pathology. It is an invasive sterile procedure, performed under local anesthesia.

Nursing Responsibilities for Liver Biopsy

• Explain the procedure to the patient
• Place the patient on NPO for 12 hours prior to biopsy
• Ensure that prothrombin and hemoglobin results are available

Potential Complications for Liver Biopsy

• Bleeding, puncture of the kidney or intestine, puncture of the lungs with subsequent pneumothorax, puncture of the gallbladder, and peritonitis are potential complications of a liver biopsy.

Endoscopic Retrograde Cholangiopancreatography (ERCP)

• The ERCP visually and radiographically inspects the liver, gallbladder, and pancreas.
• A fiberoptic duodenoscope is inserted orally under general anesthesia into the duodenum.
• Radiographic dye is introduced to visualize the liver, gallbladder, pancreas, and the different ducts.

Potential Complications for ERCP

• A perforation of the stomach, duodenum and other ducts, pancreatitis, an anaphylactic reaction to the contrast dye, aspiration of gastric contents, or a reaction to anesthesia are potential complications of ERCP.

Nursing Responsibilities for ERCP

• Confirm the signed consent form.
• Ensure a patent IV line
• Check that X-rays are available
• Keep the patient NPO for 12 hours before procedure.
• After the test: NPO until gag reflex returns.

Overview of the hepatobiliary-pancreatic system, including the liver, biliary tract, and pancreas. Focus on the liver's anatomy, including its lobes, ligaments, sinusoids, and central vein. Also covers hepatic ducts and the formation of the common bile duct.