During oogenesis, the primary oocyte undergoes meiosis I to form the secondary oocyte and the first polar body during the formation of the Graafian follicle. This occurs in the ovary. This secondary oocyte is released during ovulation and reaches the fallopian tubes (oviducts). Fertilization occurs here. When the sperm enters the ovum, the secondary oocyte undergoes the second meiotic division to release the second polar body. Also, the first polar body at the same time completes second meiotic division to form two secondary polar bodies.