Page 522 - Atlas of Histology with Functional Correlations

FIGURE 13.14 ■ Dried tooth: cementum and dentin junction. Ground and

unstained. Medium magnification.

FIGURE 13.15 | Developing Tooth (Longitudinal

Section)

A developing tooth is shown embedded in a socket, the dental alveolus (23) in
the jaw bone (9). The stratified squamous nonkeratinized oral epithelium (1,

11) covers the developing tooth and the underlying connective tissue lamina
propria (2, 12). A downgrowth from the oral epithelium (1, 11) invades the
lamina propria (2, 12) and the primitive connective tissue as the dental lamina
(3). The primitive connective tissue (8, 17) surrounds the developing tooth and
forms a dental sac (8, 17) around the tooth.

The dental lamina (3) from the oral epithelium (1, 11) proliferates and gives
rise to a cap-shaped enamel organ that consists of the external enamel
epithelium (4), the extracellular stellate reticulum (5, 14), and the enamel-
forming ameloblasts of the inner enamel epithelium (6). The ameloblasts of

the inner enamel epithelium (6) secrete the hard enamel (7, 13) around the
dentin (16). The enamel (7, 13) appears as a narrow band of dark, red-staining
material.

At the concave or the opposite end of the enamel organ, the dental papilla
(21) originates from the primitive connective tissue mesenchyme (21) and forms

the dental pulp or core of the developing tooth. Blood vessels (20) and nerves

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