Ameloblasts and odontoblasts in tooth development - advanced bell stage, human, embryo; high magnification

Stain: Azan. From top to bottom: A cell layer of the stratum intermedium; Columnar presecretory ameloblasts at the distal side (secretion area) oriented towards predentin (blue); Note a gradient from left to right in the amount of deposited collagen fibers; Tall columnar odontoblasts in an epithelioid arrangement with their secretion area close to the predentin (blue); Note well developed nucleoli, and the presence of secretion vesicles in cells at both sides of the blue predentin.