histological and histometrical study of esophagus in rabbit and guinea pig

esophagus having different tissues has a special role in the gastrointestinal tract. among different species, layers of the esophagus, have a substantial difference. also, diameter of esophagus varies in different parts of it.the information of histological structure of rabbit and guinea pig esophagus is still incomplete. therefore, the present study was conducted. therefore, for review and comparison of esophageal histology in rabbit and guinea pig, five was prepared from each animal. after the animals anesthetized with chloroform solution, their abdominal cavity were opened and then esophagus was specified. from each esophagus three samples including the upper one third, middle one third and lower one_ third were collected. then the samples of tissue were prepared and stained with hematoxylin - eosin, periodic acid-schiff and masson trichrome. results showed that in guinea pigs, all three parts of esophageal epithelium were covered by keratinized stratified squamous and in rabbit, it was covered by nonkeratinized stratified squamous. the thickness of esophageal epithelium in rabbit was more than guinea pig. in rabbit and guinea pig, muscularis mucosa was composed of dispersed bundles of smooth muscle in longitudinal sections. submucosal layer was free of glands and composed of collagen and elastic fibers and blood vessels. tunica muscularis was the thickest layer in all animals and in rabbit composed of three layers of striated muscle; inner layer and outer layer were longitudinal and the middle layer was circular. but in guinea pig it was composed of two layers of skeletal muscle; inner layer was circular and outer was longitudinal. the thickness of outer longitudinal layer was less than two others. tunica advantitia was composed of connective tissue. there was different in epithelial tissue of rabbit and guinea pig esophagus but, both animals were free of esophageal glands.