Histologie du Foie et des Voies Biliaires

Histologie du Foie et des Voies Biliaires Intra et Extra-Hépatiques

• Introduction: The digestive system transforms food into usable nutrients. The liver, the largest gland, is crucial in this process through its secretion of bile, aiding in fat digestion. The liver is a complex, amphicrine organ.
• Organisation de l'appareil digestif: The digestive system includes oral cavity with teeth, tongue, and salivary glands; the esophagus; the stomach, small intestines (duodenum, jejunum, ileum); and large intestines ending in the anus. Accessory digestive glands include the salivary glands, the liver, and pancreas.
• Rappels anatomiques: The liver is situated in the upper right quadrant of the abdomen and is protected by the ribs. It is composed of four lobes (right, left, quadrate, and caudate) with the right lobe being the largest. The gallbladder, a small sac-like organ, stores bile produced by the liver. The liver is connected to the intestines and gallbladder through ducts.
• Rappels embryologiques: Embryonic development of the liver starts at approximately the 28th day. Parts of the embryonic gut differentiate into the liver and gallbladder structures while vasculature form at 32 days.
• Structures histologiques: The liver is composed of functional units called hepatic lobules. Hepatocytes are the primary cells; they are arranged in plates. These lobules are surrounded by connective tissue. The liver is connected by bile ducts; the ducts (bile ducts) are lined with epithelium that transport bile from the liver to the duodenum of the small intestine. The liver also possesses a rich vascular network comprising the hepatic portal vein, hepatic artery, and hepatic vein, essential for blood/nutrient flow and waste removal.
• Les canalicules biliaires: Microscopic ducts between hepatocytes facilitate drainage and transport of bile.
• Les voies biliaires extra-hépatiques: The extrahepatic biliary system encompasses the cystic duct, common hepatic duct, and common bile duct. This system transports bile from the liver and gallbladder to the duodenum.
• Les nerfs: Nerves do not penetrate into actual hepatocytes, but surround the liver lobules and capillaries.
• Circulation hépatique: The blood supply to the liver originates from the hepatic portal vein, carrying nutrient-rich blood from the digestive tract, and a smaller component, the hepatic artery, which carries oxygenated blood. These two blood sources converge within the hepatic sinusoids.