SCANNING ELECTRON-MICROSCOPIC STUDIES OF DEVELOPING GUSTATORY PAPILLAE IN HUMANS

Development and morphological changes of human gustatory papillae duri ng postovulatory weeks 6-15 have been studied using scanning and trans mission electron microscopy. The first papilla of the tongue appears a round postovulatory week 6 in its caudal midline near the foramen caec um. In contrast, the dorsal epithelium of the anterior part of the ton gue shows only small hillock-or papilla-like elevations from week 6 on , which comprise an aggregation of 5-20 epithelial cells. From week 7 on, most prominent fungiform papillae develop near the median sulcus a nd at the margins of the anterior part of the tongue. At their tops, t he first primitive taste pores are found around week 10; these are oft en covered with processes of adjacent epithelial cells. Most pores, ho wever, develop around weeks 14-15. The maturation of taste buds does n ot coincide with the appearance of taste pores, since taste bud cells are not fully differentiated in the observed period of time. Fungiform papillae are developed before filiform papillae, which do not occur w ithin the first 15 weeks of gestation. Fungiform papillae tend to grow between weeks 8 and 15 of gestation, whereas the size of vallate papi llae seems to be constant during this period.