Colored scanning electron micrograph (SEM) of several capillaries running through liver tissue. The functions of the liver include destroying old red blood cells, breaking down harmful waste products and toxins in the blood, and extracting useful nutrients from the blood to make and store proteins and other useful chemicals. Numerous capillaries, veins and arteries supply and remove blood. The structure of the liver tissue allows the blood to percolate through the tissue. At any one moment, the liver holds over 10 percent of the body's blood supply. Magnification is x550 when printed 12 cm wide.