Rete ovarii

The rete ovarii (pl.: retia ovarii) is a structure formed from the primary sex cords in females. It is the homologue of the rete testis in males. It is a narrow hilus, at which nerves and vessels enter the ovary. In the medulla of the mammalian ovary near the hilus are small masses of blind tubules or solid cords — the rete ovarii. The microscopic right ovary of birds usually consists only of medullary tissue. Once thought to be a "functionless vestige" and often dismissed, the organ appears in drawings of the ovary in early versions of Gray’s Anatomy, but it disappeared from recent textbooks. The rete ovarii is important in the control of meiosis in the maturing ovary. Cells of the rete ovarii also differentiate to form granulosa cells. The rete is also attributed with secretory capacity, a hypothesis supported by the observation of secretory material in the lumen of rete tubules in several species.