MICROANATOMY OF THE EPIDIDYMIS AND VAS-DEFERENS

In this review, the structural and functional characteristics of the h uman epididymis, including vas efferens and ductus deferens, are revis ited under the morphological and ultrastructural point of view New sur face sperm antigens, enabling the fertilizing power during the epididy mal transit, various epididymal microenvironments and their activities on the spermatozoa are reported. This revision is important because t he recent procedures of assisted reproduction, aimed at overcoming the cases of obstructive azoospermia, use the spermatozoa aspirated from the proximal segments of the epididymis and suggest a flexibility of t he epididymal function with regard to the fertilizing sperm capacity. In my opinion these proce dures must be based on an accurate investiga tion on the function of the different epididymal districts. Moreover, in patients affected by congenital absence of the vas deferens (CAV), the ultrastructural examination of the spermatozoa aspirated from the proximal segments of the epididymis revealed that most of them are def ective: in fact the absence of the vas deferens seems to affect the de velopment and the functional properties of the epididymal spermatozoa.