Oogenesis & Follicular Development

What is the first stage of oogenesis?

Oogonia undergo mitosis to form primary oocytes.

What happens to primary oocytes after they are formed?

Primary oocytes start meiosis I but are arrested in prophase I and remain in primordial follicles.

What happens to the primary oocytes during childhood?

Primary oocytes remain arrested in prophase I within primordial follicles throughout childhood.

What is the process that occurs at puberty in oogenesis?

Primordial follicles develop into primary follicles, then into secondary follicles, and the primary oocyte finishes meiosis I to form a secondary oocyte and a first polar body.

What is the secondary oocyte formed during oogenesis?

The secondary oocyte is the result of meiosis I and will only complete meiosis II if fertilized.

What is the relationship between the secondary oocyte and the mature (Graafian) follicle?

The secondary oocyte is present in the mature (Graafian) follicle, which is ready for ovulation.

When does meiosis II occur in oogenesis?

Meiosis II is completed only if the secondary oocyte is fertilized.