This image is of the surface of a human red blood cell taken by AFM. The human red cell is only about 8mm in diameter, 2mm high and only 1mm thick in the center.  Notice the special biconcave shape of the cell.  This gives the cell flexibility to deform and flow through blood conduits smaller than the actual cell size without rupturing.  Capillaries, the smallest of blood conduits are only about 3mm in diameter, less than HALF the size of most human red blood cells!

To learn more about red blood cells and their special properties please visit the Osmotic Pressure in Red Blood Cell & Plant Cells module on this site.

This image was obtained using non-contact Atomic Force Microscope (AFM).