Histological description of the lower lip and the mouth commissure in local black goat

Abstract

The study included a description for the histological structure of the lower lip and mouth commissure of (six head ) of local female black goat in Mosul city. The study show presence of difference in the number of the cellular rows forming the epithelium covering lower lip and mouth commissure .The skin epidermis here composed of the known five layers of keratinized stratified squamous epithelium. The study results show presence of difference in the total thickness of epithelium and thickness of stratum cornium in (mucous membrane , transmitted zone of lip and skin) between the lower lip and mouth commissure. The mucous membrane of mouth commissure found to be with high epidemis thickness(368.6µm) in comparison with that of the lower lip(257.3µm) , while the skin of the lower lip appeared with high thickness when compared with the skin of mouth commissure .The study show presence of three types of hair follicles ; the primary and secondary hair follicles present in the skin of mouth commissure ,while the primary and tactile hair follicles present in the skin of lower lip . The glands available here were of three types ;The sebaceous glands present in large size(176.6 x 92.0µm) in skin of lower lip when compared with that of mouth commissure skin(180.6 x 55.8µm). The sweat glands were of apical secretion type in the skin of both regions. The third type of glands distinguished by pure mucous secretory units with complete duct system open with the mouth in the mucous membrane lining the mouth commissure and sub mucosa of transmitted zone of the same region . The study results show also presence of epidermal papillae in the transmitted edge of lower lip and filiform papillae in the transmitted zone of mouth commissure.