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

Stain: Azan. From top to bottom: Stellate reticulum consisting of a loose network of ectoderm-derived cells; Cell layers of the stratum intermedium; Columnar presecretory ameloblasts with their nuclear area close to the stratum intermedium, and at the distal side (secretion area) oriented towards predentin (blue); Predentin with fan-like arrangement of Korff's fibers (deep blue); Columnar odontoblasts in a epithelioid arrangement with their secretion area close to the predentin (blue); Mesenchym-derived fibroblast-like cells (so-called pulpal cells) producing collagen (thin blue threads) of the dental papilla (future pulp).