Differentiate between Graafian follicle and tertiary follicle

Dear Student, Oogonia(egg mother cells) divide by mitosis forming primary oocyte. Each primary oocyte then gets surrounded by a layer of granulosa cells called primary follicle. A large number of these follicles degenerate during the phase from birth to puberty. The primary follicle are surrounded by more layers of granulosa cells called secondary follicles. The secondary follicles soon changes into a tertiary follicle which is characterized by fluid filled cavity called follicular antrum. The tertiary follicle is further converted into mature follicle or Graafian follicle. Regards