Carpenter's principles of human physiology . ayer of cells, which are in immediate contact with the papilla, are columnar and regu-larly hexagonal in section. Theirextremities are destitute of a cell-wall, though elsewhere it is welldefined. Near the base of thepapilla the cells become morecubical, and are reflected at itsbase upon the inner surface ofthe wall of the saeculus. Thepolygonal cells intervening be-tween these two layers becomestellate and anastomose witheach other, the interspaces beingfilled with a gelatinous sub-stance, which appears to forma kind of pabulum for the growthof the
Carpenter's principles of human physiology . ayer of cells, which are in immediate contact with the papilla, are columnar and regu-larly hexagonal in section. Theirextremities are destitute of a cell-wall, though elsewhere it is welldefined. Near the base of thepapilla the cells become morecubical, and are reflected at itsbase upon the inner surface ofthe wall of the saeculus. Thepolygonal cells intervening be-tween these two layers becomestellate and anastomose witheach other, the interspaces beingfilled with a gelatinous sub-stance, which appears to forma kind of pabulum for the growthof the columnar enamel all events, it undergoes atro-phy, so that the outer and innerepithelial layers come into closeapposition; and in teeth exa-mined just at the period oferuption a membrane can bedetached from the enamel, com-posed of one or more layers ofvery flat epithelial cells, whichWaldeyer entertains no doubt represent the cuticle, with more or less of thestratum intermedium or rete mucosum. The enamel itself proceeds from the. Vertical section of the Lower Jaw of a Human Fcefus, mea-suring about four inches in length, magnified 25 diam.—1,dental groove; 2, remains of the enamel germ; 3, enamelorgan, presenting epithelium on both its outer and inner sur-face—, where it lines the saeculus and where it covers thepapilla; 4, enamel germ of the permanent tooth; 5, papilla;6, section of inferior maxilla; 7, Meckels cartilage. The den-tal saeculus will be observed to present a number of finepapilla opposite the dental papillae. CONNECTIVE TISSUES TEETH. 57 direct calcification of the long columnar cells, the deposition of the calcareoussalts taking place with tolerable uniformity in their outer ends. When thecalcification has proceeded to a certain extent, the calcified part may be raised Fig. 47.
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectphysiology, bookyear1
