SON4010 Module 5

• Couinaud's classification of the liver

  A system used to describe both the morphological and functional anatomy of the liver
• Couinaud's classification


  • Divides the liver into eight independent functional units known as segments
  • Each segment has its own vascular inflow and outflow, as well as biliary drainage
• Basis of Couinaud's classification

  Distribution of the hepatic veins and the portal veins within the liver
• Morphological anatomy


  The physical structure and arrangement of the liver's lobes, segments, vessels, and ligaments
• Functional anatomy


  How the liver's structure correlates with its physiological functions, such as metabolism, detoxification, and bile production
• Segment I (Caudate Lobe)

  Located on the posterior surface of the liver, near the inferior vena cava. It receives blood supply from the caudate branches of the portal vein and hepatic artery.
• Segment II (Left Lateral Segment)


  Located on the left side of the liver, between the falciform ligament and the left hepatic vein. It receives blood supply from the left hepatic artery and portal vein.
• Segment III (Left Medial Segment)


  Also known as the quadrate lobe, it is located on the left side of the liver, anterior to the porta hepatis. It receives blood supply from the left hepatic artery and portal vein.
• Segment IV (Left Hepatic Segment)


  The largest segment, located on the left side of the liver, between the falciform ligament and the left hepatic vein. It receives blood supply from the left hepatic artery and portal vein.
• Segment V (Anterior Superior Segment)


  Located on the right side of the liver, between the falciform ligament and the right hepatic vein. It receives blood supply from the right hepatic artery and portal vein.
• Segment VI (Anterior Inferior Segment)


  Also on the right side of the liver, between the falciform ligament and the right hepatic vein. It receives blood supply from the right hepatic artery and portal vein.
• Segment VII (Posterior Segment)

  Located on the posterior aspect of the liver, between the right and left hepatic veins. It receives blood supply from branches of the right portal vein.
• Segment VIII (Posterior Inferior Segment)


  Located on the posterior inferior aspect of the liver. It receives blood supply from branches of the right portal vein.
• Hepatic Veins


  Vessels that drain blood from the liver into the inferior vena cava, dividing the liver into the right and left lobes
• Portal Veins


  Vessels that bring nutrient-rich blood to the liver from the gastrointestinal tract, spleen, and pancreas
• Ligamentum Teres (Round Ligament)


  A remnant of the fetal umbilical vein, running within the falciform ligament and dividing the left and right lobes of the liver
• Falciform Ligament


  A fold of peritoneum that separates the right and left lobes of the liver and attaches the liver to the anterior abdominal wall
• Ligamentum Venosum


  A fibrous remnant of the ductus venosus in the fetal circulation, running within the left lobe of the liver
• Liver


  • Composed of functional units called hepatocytes, arranged in lobules
  • Hepatocytes organized around central veins and in direct contact with sinusoids
  • Portal triad consists of branches of hepatic artery, portal vein, and bile duct
• Liver filtration


  Removes toxins, metabolic waste products, and old or damaged blood cells
• Liver digestion


  Produces bile, which emulsifies fats in the digestive process
• Liver metabolism


  1. Involved in metabolism of carbohydrates, fats, and proteins

  2. Synthesizes glucose, glycogen, and cholesterol
• Liver detoxification


  Hepatocytes detoxify drugs, alcohol, and other harmful substances
• Liver protein synthesis


  Synthesizes proteins such as albumin, clotting factors, and complement proteins
• Liver vitamin storage


  Stores vitamins A, D, E, and K
• Gallbladder


  • Small pear-shaped organ located beneath the liver
  • Stores and concentrates bile produced by the liver
  • Has a neck, body, and fundus
• Biliary tree


  • Consists of bile ducts that transport bile from the liver to the duodenum
  • Includes right and left hepatic ducts, common hepatic duct, cystic duct, and common bile duct
• Bile production and excretion

  1. Hepatocytes produce bile

  2. Bile transported to bile ducts and stored in gallbladder

  3. Bile contains bile salts that aid in fat digestion and absorption

  4. Gallbladder contracts upon food ingestion, releasing bile into duodenum
• Pancreas


  • Glandular organ located behind the stomach, extending horizontally across the abdomen
  • Has a head, body, and tail
  • Uncinate process is a small extension of the pancreatic head
• Pancreatic duct


  • Main duct runs through length of pancreas and joins common bile duct before entering duodenum at ampulla of Vater
• Pancreatic vascular anatomy


  • Receives blood supply from branches of celiac axis, superior mesenteric artery, and splenic artery
  • Venous drainage through splenic vein, which joins superior mesenteric vein to form portal vein
• Pancreatic endocrine function


  Secretes hormones like insulin, glucagon, somatostatin, and pancreatic polypeptide to regulate blood sugar, digestion, and nutrient absorption
• Pancreatic exocrine function


  Secretes digestive enzymes like proteases, lipase, and amylase to aid in digestion of proteins, fats, and carbohydrates
• Hepatitis


  Inflammation of the liver, commonly caused by viral infections (hepatitis A, B, C, D, and E viruses) or by non-viral factors such as alcohol, drugs, or autoimmune diseases
• Common Complications of Hepatitis


  • Jaundice (yellowing of the skin and eyes due to bilirubin buildup)
  • Fatigue
  • Nausea
  • Vomiting
  • Abdominal pain
  • Dark urine
  • Clay-colored stools
• Hepatitis LFTs


  Elevated levels of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST), elevated bilirubin levels, and abnormal alkaline phosphatase (ALP) levels may be observed
• Cirrhosis


  A late stage of scarring (fibrosis) of the liver caused by long-term liver damage. Common causes include chronic alcohol abuse, viral hepatitis, non-alcoholic fatty liver disease (NAFLD), and autoimmune hepatitis
• Common Complications with Cirrhosis

  • Portal hypertension
  • Ascites (accumulation of fluid in the abdominal cavity)
  • Hepatic encephalopathy (neurological dysfunction due to liver failure)
  • Esophageal varices (dilated veins in the esophagus)
  • Hepatocellular carcinoma
• Cirrhosis LFTs


  Elevated serum bilirubin, decreased serum albumin levels, elevated prothrombin time (PT), elevated AST and ALT levels, and elevated ALP levels may be observed
• Hepatocellular Carcinoma (HCC)


  The most common type of primary liver cancer, arising from hepatocytes. It often occurs in the setting of chronic liver disease, such as cirrhosis, and is associated with risk factors such as hepatitis B and C infections, alcohol abuse, and aflatoxin exposure