. Principles of human physiology : with their chief applications to pathology, hygiene, and forensic medicine : especially designed for the use of students. , and four or five for the molars. At the fourteenth week theinner lip of the dental groove has increased so much, as to meet and apply itself in avalvular manner to the outer lip or ridge, which has been also increasing. The fol-licles at this time grow faster than the papillae, so that the latter recede into the primitive dental groove then contains ten papillae, enclosed in as many follicles;and thus all necessary provision i
. Principles of human physiology : with their chief applications to pathology, hygiene, and forensic medicine : especially designed for the use of students. , and four or five for the molars. At the fourteenth week theinner lip of the dental groove has increased so much, as to meet and apply itself in avalvular manner to the outer lip or ridge, which has been also increasing. The fol-licles at this time grow faster than the papillae, so that the latter recede into the primitive dental groove then contains ten papillae, enclosed in as many follicles;and thus all necessary provision is made for the production of the first set of teeth.(This series of changes is represented in Fig. 57, a—g.) The groove is now situated,however, on a higher level than at first; and it has undergone such a change by theclosure of its edges, as to entitle it to the distinctive appellation of secondary dentalgroove. It is in this secondary groove, that those structures originate, which aredestined for the development of the second or permanent set of teeth,—of those atleast which replace the milk teeth. This is accomplished in the following Diagrams illustrative of the formation of a temporary, and its corresponding, permanent tooth,from a mucous membrane. (After Goodsir.) b. At about the fourteenth or fifteenth week, a little crescentic depression may beobserved, immediately behind the inner opercula of each of the milk-tooth depression gradually becomes deeper, and constitutes what may be termed acavity of reserve, adapted to furnish delicate mucous membrane for the future forma-tion of the sacs and pulps of the ten anterior permanent teeth. These cavities ofreserve are gradually separated from the secondary dental groove, by the adhesionof their edges; and they thus become minute compressed sacs, situated between thesurface of the gum and the milk-sacs. They gradually recede, however, from thesurface of the gum, so as to be posterior instead of infe
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Keywords: ., bookcentury1800, bookdecade1840, bookpubli, booksubjectphysiology
