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Fig. 252. Section of developing tooth from a 3 months human fetus

Szymonowicz.

The dental shelf is at first of uniform thickness, but in a short time five enlargements appear in it in each upper and lower jaw, indicating the beginnings of the milk teeth. When the embryo reaches a length of 40 mm. (an age of eleven to twelve weeks) the mesenchymal tissue on one side of these enlargements (above and to the inner side in the upper jaw, below and to the inner side in the lower jaw) becomes condensed and pushes its way into the epithelium. Each of these mesenchymal ingrowths is a dental papilla. Thus at this stage the anlage of each tooth is a mass of epithelium fitting cap-like over a mesenchymal papilla. The epithelium is the forerunner of the enamel organ; the papilla is destined to give rise to the dentine and pulp. The anlagen are connected with one another by intermediate portions of the dental shelf, and with the surface by the original ingrowth of epithelium.


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Pages where the terms "Historic" (textbooks, papers, people, recommendations) appear on this site, and sections within pages where this disclaimer appears, indicate that the content and scientific understanding are specific to the time of publication. This means that while some scientific descriptions are still accurate, the terminology and interpretation of the developmental mechanisms reflect the understanding at the time of original publication and those of the preceding periods, these terms, interpretations and recommendations may not reflect our current scientific understanding.     (More? Embryology History | Historic Embryology Papers)

Reference

Bailey FR. and Miller AM. Text-Book of Embryology (1921) New York: William Wood and Co.



Cite this page: Hill, M.A. (2024, March 4) Embryology Bailey252.jpg. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/File:Bailey252.jpg

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current11:35, 21 January 2011Thumbnail for version as of 11:35, 21 January 2011904 × 690 (166 KB)S8600021 (talk | contribs){{Template:Bailey 1921 Figures}} Category:Human Category:Gastrointestinal Tract