Maksavyöhykkeitä

Maksavyöhykkeitä, often translated as liver zones or hepatic lobules, are the microscopic functional and structural units of the liver. In mammals, the liver is organized into thousands of these hexagonal structures. Each maksavyöhyke is composed of cords of hepatocytes, which are the main liver cells, radiating outwards from a central vein. Between these cords are hepatic sinusoids, which are small blood vessels that carry blood from branches of the hepatic artery and portal vein towards the central vein.

The maksavyöhyke is organized around the flow of blood and bile. Blood enters the lobule from the portal triad, located at each corner of the hexagon, and flows through the sinusoids, where hepatocytes can extract nutrients, process toxins, and synthesize proteins. Bile, on the other hand, is produced by the hepatocytes and flows in the opposite direction, towards bile canaliculi which eventually lead to the bile ducts in the portal triad.

While the hexagonal maksavyöhyke is the classic model, other organizational patterns exist, such as the hepatic acinus and the hepatic portal lobule, which emphasize different functional aspects of liver physiology. Regardless of the model used, the maksavyöhyke represents the fundamental organizational unit responsible for the liver's diverse metabolic, detoxification, and synthetic functions.