Histologic Description of the Different Segments from the Ostrich Respiratory System (Struthio camelus var. Domesticus)

Abstract

Due to the growing interest of the ostrich industry (Struthio camelus var. domesticus) and the scarce bibliographic material related to morphology of the respiratory system of the ostrich, we carried out a comparative analysis of the laryngotracheal pulmonary segment of this bird. The research was conducted in six clinically healthy ostriches from which representative samples of the laryngotracheal pulmonary segment were obtained. Samples were processed using standard histological technique and a comparative morphological analysis between ostriches and chicken (Gallus gallus) was performed. In the ostrich, the arytenoid cartilage is double and placed in a dorsal and cranial position in relation to the larynx while the cricoid cartilage is single and situated in a ventral and caudal position. Like the chicken, the procricoid cartilage is also present. The trachea exhibits a greater number of rings compared to the chicken. At the syrinx level, the pessulus is made up of a dorso-ventral double-fold of mucous membrane with a lamina propria of dense connective tissue over a thick adipose layer. Unlike the chicken the ostrich pessulus does not contain any ossified or cartilaginous tissues. The mucosa between the larynx and secondary bronchi has a pseudostratified prismatic ciliated epithelium with mucous goblet cells with crypts and simple tubuloalveolar mucosal glands for mucous secretion. In the extrapulmonary primary bronchi this histological feature is observed only in the medial aspect where the ends of the cartilaginous rings are found. The remaining mucosa of these bronchi has a pseudostratified prismatic ciliated epithelium with mucous goblet cells. Aerial sacs show this histological feature in some sectors.