Histologic developmental horizons of the prenatal dromedary tongue

Abstract

We present a study on the histologic developmental horizons of the dromedary tongue using abattoir samples. The 13 month dromedary gestation period was divided into four quarters, giving the dromedary four prenatal growth phases. Feotuses were recovered from slaughtered camels and 1 cm 2 samples were cut from dorsum and lateral parts of the apex, body and base of tongues of associated foetuses in each growth phase for histological analysis. The dorsal and lateral parts of the apex of the tongue showed variable sizes of underdeveloped filiform and fungiform papillae formed from the folding of non-keratinized stratified squamous epithelium. The filiform papillae were interspersed with fungiform papillae. A brief glandless propria-submucosa of vascularized connective tissue was continuous with their lamina epithelialis. The muscularis showed vertical, longitudinal and transverse (X, Y, Z) directions of skeletal muscles. Same arrangement was found at the lingual body. Underdeveloped lentiform papillae extended from the terminus of the caudal aspect of the lingual body to the rostral aspect of the lingual base. The lingual base showed underdeveloped fungiform and vallate papillae. The lingual body and base were highly muscularized. The muscularity became more obvious at the second and third quarters. Unique to the third phase was apical keratinization of filiform papillae, marking its full development. The propria-submucosa was highly vascularized. The fourth growth phase marked the stage for full development of most of parts of the tongue except the mucosa of the lingual base, where taste buds were not observed in gustatory papillae, eventhough an earlier study had observed taste buds in gustatory papillae of the adult dromedary. It was concluded that most of the salient features of the postnatal dromedary tongue, such as gustatory and non-gustatory papillae, were already evident as early as the first growth phase.