Epididymis 400x (OsO₄ stain): Note the pseudostratified columanr epithelium which forms the epididymis tubule. You can barely see the stereocilia (microvilli) (better seen in the next slide) which project into the tubule. These are important in secretion and absorption to maintain the environment around the spermatozoa which mature here. Note the thin layer of smooth muscle around the epididymis, which functions during emission and ejaculation.