Hello and welcome to the Zero to Finals podcast. My name is Tom and in this episode I'm going to be

talking to you about ovulation, conception and implantation. And if you want to follow along with written

notes on this topic, you can find them at zero tofin0.com slash ovulation conception implantation

or in the reproductive system section of the 0.2 finals obstetrics and gynecology book.

So let's get straight into it.

Inside the ovaries, the primordial follicles each contain a primary oocyte.

The oocytes are the germ cells, the first generation of

sex cells, that undergo meiosis to become the mature ovum, which is the egg ready for fertilization.

The oocytes contain the full 46 chromosomes that are found in all cells of the body. These primordial

follicles and oocytes spend the majority of their lives in a resting state inside the ovaries

waiting for their time to develop. The follicles go through four stages of development that you

need to be aware of prior to ovulation or releasing the ovum.

And these stages are primordial follicles where they spend the majority of their lives.

These transform into primary follicles, then secondary follicles and then antral follicles.

And we'll go into more detail about these

stages of development. In terms of the structure of the primordial follicles, the primary

oocyte is contained within the pre-granulosa cells, which is surrounded by the outer basal

laminar layer.

Let's talk about the development of the primary follicle.

The primordial follicles grow and become the primary follicles.

These primary follicles have three layers.

In the center, there's the primary oocyte. This is surrounded by the Zona

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