Microvasculature of the Epididymis and Ductus Deferens of Domestic Fowls

Abstract

The microvasculature of the fowl epididymis and ductus deferens was studied by scanning electron microscopy of microvascular corrosion casts and by light and transmission electron microscopy. The interstitial tissue of the rete testis was poorly endowed with irregularly arranged capillary network, while it was penetrated by several testicular arteries and veins. Histologically, the capillaries ran through the interstitial tissue without close regional relations to the epithelium of the rete testis. They were rarely fenestrated. The individual excurrent ducts from the efferent ductules to the ductus deferens were encircled by dense peritubular capillary networks. The capillaries were located just beneath the epithelium. Their endothelial cells with rich pinocytotic vesicles were attenuated on the side toward the epithelium of the excurrent ducts and were fenestrated. Horseradish peroxidase injected into the vessels flowed out rapidly through the fenestrations and/or was transported via the pinocytotic vesicles into the extravascular areas and the intercellular spaces between the epithelial cells of the excurrent ducts. These findings suggest that in the fowl a possible active exchange of materials may occur between the respective capillaries and the epithelium of the excurrent duct systems, except in the rete testis.