What happens to the tertiary follicles if the secondary follicles survive?

Follicles:

1. These are membrane-bound vesicles that contain nutrient-rich stroma.
2. They exist in different developing stages in the ovary.
3. One of the follicles enlarges in size and contains the ovum released by the ovary.
4. It is known as the Graafian follicle.
5. The rupture of this follicle leads to the release of the ovum.
6. The ruptured Graafian follicle converts into the corpus luteum that secretes progesterone for the thicking of the endometrial lining of the uterus.
7. In case of no fertilisation, this lining sheds, and a new menstrual cycle begins.

Thus, in case the developing secondary follicle survives:

1. The tertiary follicle grows in size.
2. It forms distinctive layers: the theca externa, theca interna, a fluid-filled antrum, and the zona granulose.
3. It becomes highly vascularised and rich in nutrients.