Coloured scanning electron micrograph (SEM) of a freeze-fracture through olfactory tissue from a 16 day old mouse embryo. This is pseudostratified epithelium with a basement membrane (grey) and characteristic microvilli on the upper surface (light pink). Nuclei are brown and mitochondria are violet. The picture was created as part of a cooperation with Quintessenz Publishing. Magnification: x4000 when printed at 15cm wide.