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Abstract
The epididymis is an important organ that has several causes of dysfunction. Studying these causes may help
understanding several factors that affect male fertility.
It is also an organ that has a great role in sperm maturation, storage and
capacitation. In addition it was found that the epididymis can be a target as a male contraception.
from the anatomical point of view, the epididymis in its full developed state is a coma shaped structure clasping the
posterior aspect of the testis and to some extent overlapping the posterior part of its lateral surface.
Histologically, the lumen of efferent ductules is lined with 2 types of cells; ciliated and non-ciliated cells. The ciliated cells are present in all sections of the efferent ductules while the secretory non-ciliated cells predominate in the proximal portion
and the non-ciliated cells with absorptive function predominate
in the distal portions of the efferent ductules.
The epithelium of the ductus epididymis is formed mainly from principal cells and basal cells. The principal cells
are high columnar cells. They have secretory and absorptive activity. The basal cells are pyramidal in shape with no morphological evidence permits to assign a precise function to them. In addition, to these two types of cells there are some other types described by some investigators, which are the
holocrine cells, the apical cells and clear cells.
The epididymis acts as the mechanical pathway through which the spermatozoa are transported from the testis to the vas deferens. This is achieved by the contractility of smooth muscle
surrounding the epididymal duct, the positive pressure of the fluid coming from the testis and by the cilia propulsion in the efferent ductules. Then at the cauda epididymis the
spermatozoa remain stored in a quiescent state before they are
ejaculated.
Sperm storage in the cauda is controlled by the frequency of ejaculation, temperature and androgens, mainly dihydrotestosterone and to less extent testosterone.
Androgens influence the capacity of the epididymal epithelium for absorption and secretion. Deficiency of androgen evokes a significant response through inhibiting fluid resorption by the
caudal epithelium. This decreases concentration of sperms in the ejaculatory ducts. Androgens reach the epididymis via the arterial circulation or from the testis with rete testis fluid or by in situ synthesis (dihydrotestosterone from testosterone).