Caption

Liver vein. Coloured scanning electron micrograph (SEM) of a freeze-fractured section through liver tissue showing the central vein in a liver lobule. Red blood cells (erythrocytes, red) are also seen. Blood in each of the many liver lobules drains into a central vein to return to the heart. The openings of several sinusoids, capillaries which carry blood through a lobule, are seen at lower left. The sinusoids allow blood to exchange gases and nutrients with liver cells (hepatocytes), which help to regulate sugar and fat levels in the blood. The sinusoids receive nutrient-rich blood from the intestines and oxygenated blood from the heart. Magnification unknown.