Figure 5. Photomicrographs of the early stages of human preantral folliculogenesis. A) Primordial follicle; arrow, squamous granulosa cell. B) Recruitment showing the primordial-to-primary transition; arrow, cuboidal granulosa cell. C) Primary follicle with multiple cuboidal granulosa cells. D) fully grown primary follicle at the primary-to-secondary transition stage; arrow, formation of a secondary layer of granulosa cells. All photos are 40x.