ANATOMICAL, HISTOLOGICAL AND HISTOCHEMICAL STUDIES OF ORBITAL GLANDS OF LITTLE OWL ATHENE NOCTUA

Abstract

The present study aimed to illustrate the anatomical, histological and histochemical structure of the two orbital glands of the little owl, Athene noctua with revealing their role in the vision. In little owl, the size of lacrimal gland appears smaller than that of the Harderian gland. The Harderian gland of the little owl is flat and looks like teardrop in shape with pink color and located between the ventralis oblique muscle and pyramidalis muscle. While, the lacrimal gland is cylindrical, compressed in the dorsal-ventral direction and is located on the dorsal edge of the orbit within a narrow elongated fossa. Both glands are compound tubuloalveolar type. The acini of Harderian gland are lined by cuboidal glandular cells whereas the lacrimal gland acini are lined by columnar cells. The Harderian gland in the little owl is classified as a type I. The Harderian gland and lacrimal glands of the little owl contain neutral and acid mucosubstances. INTRODUCTION