Prenatal development of the lingual epithelium in goat (Capra hircus)

The present study was conducted on the tongue of 18 goat foetii divided into three prenatal age groups viz- Group I ( below 50 days of gestation), Group II ( between 50-100 days of gestation) and Group III ( above 100 days of gestation to up to full term) containing 6 number of foetii in each group to study the sequential events in regard to histological development of the same in goat foetii. The tongue was lined by 3-4 layered epithelium in the foetus at 40 days of gestation (CRL= 2.40cm). The lingual epithelium consisted of a basal layer of cuboidal cells with squamous to cuboidal shaped more superficial layers. At 62 days of gestation (CRL= 10.10 cm), the lamina epithelialis of the tongue of goat foetus was distinctly stratified. At this stage of development, the epithelial layers could be divided into dark basal and a light apical or superficial zones. At 80-84 days of gestation (CRL=15.3 to 16.0 cm), the stratified squamous epithelium of the tongue was better developed both on the dorsum and ventral surfaces. At 93 days of gestation (CRL= 20.6 cm), the stratified squamous epithelium of the tongue was well developed and all the layers of the epithelium could be observed. In the foetii of gestational age of 100 days onwards, the lingual epithelium of the tongue showed various degrees of keratinization. Thus, it was concluded that the tongue of goat was lined with 3-4 layers of epithelial cells. The degree of stratification increased with an increase in gestational age. Also with age there was an increase in the degree of keratinization. This research further implicated that with further advancement of age the basal layer of the epithelium comprised high cylindrical cells along with well defined basement membrane. The decrepancy of histogenesis and keratogenesis between different species may be due to difference in the duration of the gestation period.