Title: Odontoblast in tooth development
Scheme electron microscopy, human embryo. A columnar and irregular shaped cell (mesenchymal origin) with a taperwise odontoblastic process in the predentin. The bottom side is adjacent to the future pulp cells. The cell body contains many organelles and especially a well-developed Golgi area with presecretory granules.
A cell web delimits the process from the supranuclear cytoplasm and laterally small junctional complexes (gap junctions) are localized.
Title: Presecretory ameloblast in tooth development
Scheme electronmicroscopy, human embryo. The ectodermal-derived cell appears as tall columnar with fingerlike extensions (dependent on the development stages) at their distal side (secreting area=’functional base’). These extensions are formed as the cell withdraws during the production of initial enamel. The supranuclear area is well developed with a large Golgi area and secretion granules.
Title: Ameloblasts and odontoblasts in tooth development (advanced bell stage)
Scheme electronmicroscopy, human embryo.
Description: 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).
Title: Advanced bell stage with ameloblasts and odontoblasts in tooth development
Stain Azan, human embryo. 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 Korff’s fibers.
- 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.
Keywords/Mesh: oral cavity, mouth, tooth development, ameloblast, enamel, odontoblast, predentin, histology, embryology, electron microscopy, POJA collection