False-colour scanning electron micrograph (SEM) of the surface peritoneal layer of cells around the liver. Covered with many short microvilli (hair- like structures), these flattened serosal cells form an organ holding sac around the liver. Its surface area, increased by the microvilli, secre- tes fluid derived from blood serum: this allows a frictionless movement of the liver within the abdomen. Such a protective layer for organs is important, especially in the abdomen, where many organs coexist and function during body movement. Beneath microvilli the outline of individual cells can be seen. Magnification: x1,125 at 6x7cm size. Magnification: x1,800 at 4x5 inch size.