Coloured scanning electron micrograph (SEM) of a section through a human tooth. At top is the enamel, the outer covering of the crown (visible part) of the tooth. It is the hardest material in the human body. Below it is the dentine, a mineralised connective tissue that forms the bulk of the tooth. Within the dentine are dentine tubules (brown). The tubules carry nutrients from the inner pulp of the tooth, which contains the blood vessels and nerves, throughout the dentine. They also transmit sensations from the outside of the tooth to the inside. The picture was created as part of a cooperation with Quintessenz Publishing. Magnification: x2000 when printed at 15cm wide.