The fine structure of the Harderian gland in the ostrich (Struthio camelus)

The Harderian gland of the ostrich (Struthio camelus) is a tubuloalveolar gland containing holocrine secreting epithelial cells. The gland epithelium is composed of two different cell types, which can be classified as type I and type II. These cells contain dense secretory vesicles in their cytoplasm and they are connected laterally with desmosomes. At the basal site of these cells, myoepithelial cells are present. Plasma cells are observed in the subepithelial region of the gland. In the interlobular trabeculae, forming the gland stroma, fibroblasts, blood vessels and nerve fibres are included. Another important finding in the ostrich Harderian gland is the presence of homogeneous material.