The ampulla ductus deferentis in man, as viewed by SEM and TEM.

The epithelium of the human ampulla consists of rare basal cells and a single type of principal (secretory) cells. The principal cells, which vary in height from cuboidal to columnar, often have conical or club shaped apical portions projecting and bulging into the lumen. Their cytoplasm contains an abundant rough-surfaced endoplasmic reticulum, numerous mitochondria, and many lipopigment granules. The Golgi apparatus is well developed and originates the secretory vacuoles which are discharged by exocytosis. Though the majority of nuclei are ovoid, deeply fissured or even lobated nuclei are not uncommon. The basal cells are small, nonsecretory cells, whose cytoplasm shows numerous filaments having a diameter of 55 A. The lumen contains masses of amorphous secretions and some spermatozoa. The human ampulla is a gland endowed with the same morphological features as those of the seminal vesicles.