The differences in the eyelids microstructure and the conjunctiva ‐associated lymphoid tissue between selected ornamental and wild birds as a result of adaptation to their habitat

Abstract
The aim of the study was to describe the morphology of the upper, lower and third eyelid and characterize the organized lymphoid follicles and diffuse lymphocytes from ornamental and wild birds. The goal of these examinations was also to identify avian conjunctiva‐associated lymphoid tissue (CALT) and lymphoid tissue that contained specialized high endothelial venules. The upper, lower and third eyelid from 30 species of ornamental and wild birds representing 21 families were examined under light microscopy and using scanning electron microscopy. The third eyelid in all of the examined birds was composed of a free margin, which was divided into two parts. The largest tarsal plate of the third eyelid was observed in the greater rhea (Rheimorphae), the white‐tailed eagle and steppe eagle (Accipitrimorphae) and was approximately 13–15 mm wide and 9–11 mm long, respectively. In all of the examined birds, the CALT was associated with a rich network of small vessels. In addition, the presence of characteristic high endothelial venules and roundish bright endothelial cells was confirmed in the upper and lower eyelids or only in the lower eyelid (Phoenicopterimorphae, Procellariimorphae and Strigimorphae).

Source: Acta Zoologica - October 1, 2017 Category: Zoology Authors: Joanna E. Kle ćkowska‐Nawrot, Karolina Goździewska‐Harłajczuk, Dariusz Łupicki, Krzysztof Marycz, Tomasz Nawara, Karolina Barszcz, Artur Kowalczyk, Joanna Rosenberger, Ewa Łukaszewicz Tags: ORIGINAL ARTICLE Source Type: research