Epididymis, transmission electron micrograph (TEM). The epididymal epithelium is a pseudostratified columnar epithelium with long stereocilia extending from the apical surface facing the epididymal lumen. Tight junctions join cells subjacent to the lumen. The epididymis serves to confer motility and maturation on the sperm which pass through it. It secretes many proteins and absorbs ions and water. Magnification: x3,000 when height printed at 10cm.