Advanced bell stage with ameloblasts and odontoblasts in tooth development - human embryo

Stain: Azan. From top to bottom: Stellate reticulum consisting of a non-vascularized network of ectoderm-derived cells; Cell layers of the stratum intermedium; Columnar (presecretory) ameloblasts with their upper side (nuclear area) in close contact with 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); Tall columnar odontoblasts in a epithelioid arrangement with their secretion area close to the predentin (blue); Network of mesenchymal derived fibroblast-like cells (so-called pulpal cells) in the dental papilla (future pulp); note blood vessels.