Enamel in longitudinal section of tooth - human, adult. Thin ground section.

Enamel is compact and acellular, and consists of vertical stacks of rods (prisms) as well as interrod (interprismatic) regions with less calcifying substance parallel to each other. Each prism is surrounded by an enamel sheath (a non-mineralized organic substance). From left to right: surface of enamel; the parallel arrangement of stacks is evident; one light track represents one stack of rods (prisms); the dark parallel lines represent the interrod substance.