* Oogonium: The starting point. It undergoes mitotic divisions to create more oogonia.
* Primary Oocyte: The oogonium enters meiosis, but pauses at Prophase I. It remains in this stage for a long time, even years.
* Secondary Oocyte and First Polar Body: When stimulated by hormones, the primary oocyte completes Meiosis I, forming a secondary oocyte and a smaller cell called the first polar body. The first polar body contains half of the original chromosome number but little cytoplasm.
* Ovum and Second Polar Body: The secondary oocyte continues to Meiosis II, but stops at Metaphase II. This is the stage when ovulation occurs. If fertilization happens, the secondary oocyte completes Meiosis II, yielding the mature ovum (egg cell) and another smaller polar body (the second polar body).
* Polar Bodies: These are essentially discarded cellular material. They are not functional gametes and will eventually degenerate.
In summary, the oogonium undergoes several stages of cell division and maturation to produce a single, functional ovum.
