Folliculogenesis and ovogenesis are two related processes, since follicular development must be accompanied by maturation of the oocyte that the follicle contains within it.
The primordial follicles are formed by a primary oocyte, whose nucleus is arrested in meiosis I prophase. They may remain in this state for years, until they continue their development, if at all. For this, the follicle containing this primary oocyte must have reached the Graafian follicle stage. In this way, the ovulatory LH surge will enable the oocyte to continue meiosis, thus producing a secondary oocyte and the first polar corpuscle.
The secondary oocyte will again stop meiosis in metaphase II and will be ovulated into the fallopian tubes. This metaphase II stage is considered mature, since it is the stage at which the oocyte can be fertilized by a spermatozoon. In the case of fertilization, the secondary oocyte will give rise to the zygote (fertilized egg) and the second polar corpuscle.