Coloured scanning electron micrograph (SEM) of a fibroblast cell (red) grown in collagen gel. A number of active vesicles can be seen at centre. Fibroblasts are cells that produce connective tissue such as collagen, the main structural protein in the body. They also play an essential role in wound healing. The picture was created as part of a cooperation with Quintessenz Publishing. Magnification: x15,000 when printed at 15cm wide.