Ameloblasts and odontoblasts in tooth development - advanced bell stage, human, embryo CR 80 mm

Scheme electronmicroscopy. From top to bottom: Stellate reticulum consisting of a non-vascularized network of ectoderm-derived cells continuous with the 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) their basal lamina close to the predentin; Epithelioid arranged odontoblasts with irregular extensions into the predentin (collagen fibers type I in extracellular matrix); In close contact with the odontoblasts (basal nuclei) the network of fibroblast-like cells (so-called pulpal cells) producing collagen of the dental papilla (future pulp).