What are secondary follicles?

Secondary follicles:

1. At birth, the ovaries of a female are enclosed by a layer of ovarian cells and primordial cells called primary follicles.
2. At puberty primary follicles undergo meiosis to become the Graafian follicles or secondary follicles.
3. At ovulation, the Graafian follicles burst open to release a mature ovum, surrounded by later follicle cells.
4. After the ovulation process, the remains of secondary follicles change into a yellow body called corpus luteum/tertiary follicles.