Anatomical, scanning electron microscopy, histological and histochemical studies of the orbital glands of the Egyptian agama Trapelus mutabilis

Abstract Background The orbital gland of the group agama (Agamidae) is not well-studied. Here a first description anatomical and histological studies on Egyptian Trapelus mutabilis . Results Harderian (HG) well-developed, with tongue shape, appearing whitish in color, reaching approximately 1.47 mm length. can be divided into head tail regions lies at medial corner orbit ventral to ventralis oblique muscle dorsal medialis rectus muscle. Secretory product HG released conjunctival fornix, which deep nictitating membrane. compound tubuloacinar type, consisting columnar pyramidal glandular cells rounded nuclei lumina that are variable size containing pigments connective tissue capsule envelops portion this gland. react positively periodic acid-Schiff (PAS) alcian blue staining pH 2.5. In contrast, lacrimal (LG) reduced mucous appears opens surface by numerous orifices base membrane, reaches 0.1 composed simple tubulo-acini narrow lumen basal oval-shaped exhibits weak response PAS but strong Conclusions Morphology LG isn't impacted features orbit, such as existence or absence membrane and/or fixed movable eyelid. small does affect performance its main function lubricating cornea. pigmentation envelope allows heat absorbed order increase secretion activity, thereby increasing protection eyes against mechanical damage. Finally, both glands may play secondary digestion via indirect connection oral cavity.