Histology - Epididymis

Epididymis

A long, coiled tube that stores developing sperm (and contributes a small amount of seminal fluid).
Has a ring of smooth muscle; gradually thickens as the epididymis transitions to the ductus deferens.
Epithelial lining comprises:

Columnar (aka, principle) cells; they are tall and irregularly shaped, with stereocilia projecting into the lumen. The function of the sterocilia is contested, but they may increase surface area for reabsorption of fluid within the epididymis.
The basal cells have spherical nuclei that are near the base of the epithelium.