Stereocilia-Duct of Epididymis

Stereocilia (stereos, Greek: rigid, hard) are processes on the surface of epithelial cells. They line the epididymal duct and the beginning part of the sperm duct. Stereocilia and kinocilia show different morphologies and have different functions. The sperm-duct stereocilia are not motile, although flexible. In light microscopy, they have the appearance of long hairs, which often stick together in tufts 1 . Stereocilia are branched microvilli and therefore do not have kinetosomes.  The duct of the epididymis (paratestis) is lined by a double-layered Pseudostratified epithelium 2. The basal cells are usually round 3 with round nuclei, while the nuclei of Pseudostratified cells are oval. The Pseudostratified columnar epithelial cells show dot-like expansions in their apicolateral regions. These are the terminal bars (terminal web, junctional complex). Inflexible stereocilia also exist on the surfaces of the sensory cells (hair cells )  in the inner ear ( inner ear stereocilia ).

1 Stereocilia tufts

2 Oval nuclei of Pseudostratified epithelial cells

3 Nucleus of a basal cell

4 Remaining spermatozoa

5 Delicate subepithelial fiber s from the lamina propria

Stain: vanGieson iron hematoxylin-picrofuchsin; magnification: × 400

References

Kuehnel, W.(2003). Color Atlas of Cytology, Histology, and Microscopic Anatomy. 4^th edition . Institute of Anatomy Universitätzu Luebeck Luebeck, Germany . Thieme Stuttgar t · New York .