Final answer:
Ovulated oocytes can be found in the uterine tube following ovulation and are enclosed in two layers, the corona radiata and the zona pellucida. These secondary oocytes must be fertilized in the distal uterine tube. In IVF procedures, multiple oocytes are harvested from the ovary just before ovulation.
Step-by-step explanation:
Upon ovulation, the oocyte that is released by the ovary can be found being swept into and along the uterine tube (also known as the Fallopian tube). Fertilization of this oocyte typically occurs in the distal part of the uterine tube, which is essential because an unfertilized oocyte cannot survive the journey to the uterus which takes approximately 72 hours. It's important to note that the ovulated oocyte is a secondary oocyte, which is enclosed in two protective layers: the corona radiata and the zona pellucida. The corona radiata is an outer layer of cells that was formed in the ovary and remains with the oocyte upon ovulation, while the zona pellucida is a thick, transparent membrane that envelopes the cell's plasma membrane.
During a woman's menstrual cycle, follicular development leads to the maturity of the follicle that eventually ruptures to release the secondary oocyte. This process is facilitated by hormonal influences, primarily follicle-stimulating hormone (FSH) and luteinizing hormone (LH). In assisted reproductive technologies such as in vitro fertilization (IVF), a similar process is used to harvest multiple oocytes. A course of gonadotropins is administered to encourage the maturation of multiple follicles, and just before these ova are released, they are retrieved through a process called ultrasound-guided oocyte retrieval.