Final answer:
During oogenesis, the structures that usually disintegrate are the polar bodies. These are formed during the meiotic divisions of the oocyte but do not develop further and instead degrade.
Step-by-step explanation:
The structures that usually disintegrate during oogenesis are polar bodies. Oogenesis is the process by which the female gametes, or eggs, are produced. During this process, the primary oocyte undergoes a series of divisions to form a secondary oocyte. If this cell is fertilized by a sperm, it completes meiosis to form the mature ovum and another polar body. Polar bodies are small cells that are formed during the meiosis of the oocyte and contain little cytoplasm. They generally degrade and do not develop into mature ova. The corpus luteum, on the other hand, originates from the follicle that released the oocyte during ovulation and eventually also degenerates if pregnancy does not occur, but it does not disintegrate during oogenesis itself.