Histological structure of the cervical segment oesophagus in goats and sheep (Comparison study)


Twelve adult animals of both goats and sheep were used in this study. The segments of oesophagus from the anterior 3rd (cervical part) were taken from six samples of goats and six samples of sheep. The segments of 0.5cm were processed by histological techniques which were stained by haematoxylin and eosin and examined under light microscope. The results of this examination revealed that, both species of animals had the for layers which were the tunica mucosa, submucosa, muscularis and adventitia, the mucosa had stratified squamous epithelium with variable amount of keratin on its surface, the lamina properia was formed by dense connective tissue with the presence of thin zone of muscularis mucosa, while in sheep the keratin on the surface of epithelium was more and the lamina properia was thinner than goat, but the muscularis mucosa was formed by masses of smooth muscle fibers more than goat. The sub mucosa was more condensed with connective tissue in goat than sheep with the presence of medium and small sized blood vessels. In this layer in both animals. The tunica muscularis of both were formed by skeletal muscle fibers, in goat were arranged into three directions which were inner circular, middle oblique and outer longitudinal, while in sheep was found as inner circular and outer longitudinal. finally, both animals were containing outer layer of loose connective tissue called tunica adventitia and in sheep had more fat cells invaded this layer with blood vessels, fat cells and nerves.