he aim of this investigation was to determine the histological differences of anatomical regions of the ureter in Japanese quail compared with some other domestic avian species such as pigeon, European starling and fowl. Tissue samples from proximal, middle and distal regions of each ureter were obtained and stained with H & E, Alcian blue (pH 2.5), Periodic acid-Schiff, Masson’s trichrome, Verhoeff’s, and Gomori’s method for reticulum. The histology and histochemistry of the ureter showed considera- ble differences among various anatomical regions of the ureter. No significant sex-based differences were found. The primary branches of ureter were composed of tunica mucosa, submucosa, muscularis and serosa, whereas the wall of smaller branches of ureter only consisted of epithelium and connective tissue fibers. The intraepithelial glands were not found in some region of ureter. The mucosal folds and microvilli were more identified in the proximal region than those of the other regions of the organ. The simple columnar epithelium of proximal region was changed to pseudostratified columnar in other regions of the ureter. In all different regions of ureter, lymphatic tissues were not observed in the lamina propria. The thickness of the tunica muscularis increased from the proximal to the distal region of the ureter. Unusual findings of the ureter in Japanese quail were the presence of reticular, elastic and collagenous fibers in all the connective tissues of organ, isometric longitudinal folds and muscularis mucosa.

KEY WORDS: Histology; Japanese quail; Region; Sex; Ureter.