Female Gonads

Abstract

AbstractSimilar to most Cyprinidae, zebrafish ovaries are divided into left and right leaf, fixed on both sides of the abdominal cavity through the mesangium. The oocytes of zebrafish undergone primary growth stage, cortical follicular stage, vitellogenic stage and mature stage, finally exhaused into ovarian cavity. Different to spermatogenic cells in seminal vesicles, oocyte development is not synchronous. In the sexually mature zebrafish ovary, there are multiple developmental stages of oocytes at the same time. In the primary growth stage, the oocytes of zebrafish are small, mostly triangular or rectangular, with little cytoplasm and strong basophilic. With the growth, the volume increases continuously, and the oocyte enters the cortical follicular stage. The cytoplasm is rich in Golgi apparatus, endoplasmic reticulum and mitochondria, and cortical alveoli appear at the edge of oocytes, which increased in number, enlarged in volume, and extend around the nucleus. The radiation bands began to form and gradually thickened in this phase. Then the oocytes begin to form vitellogenesis, and enter the vitellogenic stage. With the accumulation of vitelline, the vitelline substances gradually fills the cortical vesicles and the whole cytoplasm. The zone radiate became thicker and forms a fence shape. The vitelline substances continues to increase and vitelline droplets fuse with each other to form a crystalline vitelline ball, and finally enters the mature stage.