Histology and Scanning Electron Microscopy of the Lower Respiratory Tract in the Adult Red Fox (Vulpes vulpes)

Abstract

MOUSSA, E. A. & HASSAN, S. A. Histology and scanning electron microscopy of the lower respiratory tract in the adult red fox(Vulpes vulpes). Int. J. Morphol., 33(1):267-274, 2015.SUMMARY: The study was conducted on a total of three adult healthy freshly killed red foxes of both sexes weighing about 4-6 kg collected from Abou Rawwash, Giza, Egypt. The wall of trachea and bronchi formed of mucosa, submucosa and adventitia. Themucosa formed of pseudostratified columnar epithelium and lamina propria. The respiratory epithelium composed of tall columnarciliated, goblet cells, basal cells, and neuroendocrine cells. Goblet cells account for about 20 to 30% of cells in the more proximal. Basalcells are relatively small triangular cells whose bases are attached to the basement membrane. The primary bronchiole is lined by simplecolumnar nonciliated to cuboidal epithelium containing some bronchiolar exocrine cells and some goblet cells. Neuroendocrine cellsconstitute about 4 to 5% of bronchial epithelial cells, attached at their bases to the basement membrane and have tapering apic es. The laminapropria consists principally of a network of capillaries, a meshwork of connective tissue fibers continuous with the basement membrane.The submucosa formed of connective tissue elements and blood vessels and devoid of Tracheobronchial glands in red fox. The adventitiacontain tracheal cartilage and muscle in trachea and bronchial cartilages and muscles in bronchi. Tracheal muscle is transverse bundlesattached to the outer perichondrium. In the bronchi, muscle is organized in transverse bundles close to the epithelium adjacent to the laminapropria and longitudinal bundles close to the cartilages. Alveoli are demarcated by septa composed of a continuous layer of epi thelial cellsoverlying a thin interstitium. The epithelial cells consist principally of type I and type II pneumocytes. SEM revealed that, the mucosalsurface of both trachea and bronchi was completely covered by cilia. There were few glandular openings or goblet cell.KEY WORDS: Scanning; Fox; Respiratory; Histology.