has part has part develops from develops from oocyte follicular cell of ovary Homo sapiens follicular fluid ovarian follicle http://upload.wikimedia.org/wikipedia/commons/c/ca/Human_ovarian_follicle.jpg https://upload.wikimedia.org/wikipedia/commons/e/e6/Primary_follicle-4.JPG egg follicle ovary follicle CALOHA:TS-0726 GAID:371 TAO:0001110 MESH:D006080 follicle of ovary UBERON:0001305 BTO:0000475 These structures are periodically initiated to grow and develop, culminating in ovulation of usually a single competent oocyte in humans. These eggs/ova are only developed once every menstrual cycle (e.g. once a month in humans) Wikipedia:Ovarian_follicle MAT:0000449 Examination of different vertebrate species shows that the adult gonad is remarkably similar in its morphology across different phylogenetic classes. Surprisingly, however, the cellular and molecular programs employed to create similar organs are not evolutionarily conserved.[uncertain][VHOG] SCTID:361111009 UMLS:C0018120 The somatic cell component of the follicle produces hormones important for oocyte development and proper endocrine function MA:0001707 VHOG:0001536 Oocyte development of zebrafish has been divided into five stages based on morphological criteria and on physiological and biochemical events. Stage I follicles (less than 140 microns) are primary growth stage, stage II follicles (140-340 microns) are cortical alveolus stage, stage III (340-690 microns) are vitellogenesis, stage IV (690-730 microns) are oocyte maturation, and stage V follicles are matured egg. Selman et al, 1993.[TAO] NCIT:C33244 follicle of ovary viewed macroscopically EMAPA:35627 ZFA:0001110 FMA:18640 A spherical aggregation of cells in the ovary that contains a single oocyte[WP,modified]. TODO - align subtypes based on staging, which is taxon-specific folliculi ovarici primarii folliculi ovarici vesiculosi mesoderm-derived structure ovary sex cord egg follicle