[Scanning electron microscopic observations of microcorrosion casts for rabbit ovarian vasculature before ovulatory...

Ovarian vasculature of juvenile and adult rabbits was studied using a method of resin injection-corrosion casts. Arteries and arterioles in the ovarian stroma and capillary networks surrounding the follicles were observed on a three dimensional scale by scanning electron microscopy with the following findings: 1) The strongly coiled arteries are observed in adult rabbit ovaries. The first order arterioles arise from the spiral artery, and the second order arterioles stemming from these first order arterioles enter into each follicle. 2) Vasculature of follicles starts as glove-finger-like ramified capillary networks. As follicles grow, follicular vessels increase remarkably and form multilayered complex vascular networks surrounding the follicles. 3) The observations of circular impressions around the arterioles near the follicle and in the follicular wall suggest the existence of sphincteric control mechanism of blood flow into the follicle. 4) There are several pathways of venous drainage from a wall of large follicle and arterio-venous shunts are observed in the wall of such follicles. These structures may exert an important effect upon the follicular hemodynamics in the process of follicle rupture.