Figure 21. Photomicrograph showing the effects of the LH/FSH surge on egg-cumulus expansion in situ. The oocyte has resumed meiosis, the corona radiata is radiating from the zona pellucida, and the cumulus, (but not the membrana and periantral), granulosa cells have lost their attachments and appear as individual cells dispersed within the proteoglycan matrix, due to mucification. (Testart J, Thebault A, Frydman R, Papiernik E: Oocyte and Cumulus Oophorus Changes Inside the Human Follicle Cultured with Gonadotropins: In Hafez ESE, Semm K (eds) In Vitro Fertilization and Embryo Transfer. Alan R. Liss Inc., 1982 with permission from Jacques Testart)