levercellen

Levercellen, or hepatocytes, are the main parenchymal cells of the liver. They are polygonal, typically 20–30 micrometers in diameter, and often binucleate. They reside in plates that radiate from the central vein, located between sinusoids in liver lobules. Bile canaliculi formed by hepatocyte membranes converge toward bile ducts in the portal triads.

Anatomy and microstructure: Hepatocytes exhibit abundant organelles, including endoplasmic reticulum, Golgi apparatus, mitochondria and peroxisomes. The liver lobule is organized with a portal triad at each corner and a central vein in the middle. Blood from the portal vein and hepatic artery flows through sinusoids toward the central vein, while bile is secreted into canaliculi and drained toward the bile ducts.

Functions: Hepatocytes perform most of the liver’s metabolic tasks. They regulate carbohydrate metabolism (glycogenesis, gluconeogenesis), lipid metabolism (lipoprotein synthesis, fatty acid oxidation), and protein synthesis (albumin, clotting factors). They detoxify xenobiotics through phase I and II reactions, involving cytochrome P450 enzymes, and conjugate and excrete products in bile. They also synthesize bile acids, conjugate bilirubin, and store glycogen, vitamins and minerals. Immune modulation is supported by cytokine production from these cells.

Regeneration and zonation: Hepatocytes can proliferate in response to injury, giving the liver a remarkable regenerative capacity. Liver tissue shows zonation along the porto-central axis, with periportal zone 1 and perivenous zone 3 exhibiting different oxygen levels and enzyme expression, influencing metabolism and detoxification.

Clinical relevance: Hepatocyte injury underlies many liver diseases, including viral hepatitis, alcoholic and non-alcoholic fatty liver disease, and cirrhosis. Hepatocellular carcinoma originates from hepatocytes, and drug-induced liver injury often involves hepatocyte toxicity.