The ovaries are two almond-shaped structures that sit on either side of the uterus, connected to the uterine tubes. They produce oocytes (egg cells), as well as estrogen, progesterone, and other hormones. Egg cell production, or oogenesis, begins with the primordial follicles. As girls reach puberty, each ovary contains thousands of these follicles, and each follicle contains a primary oocyte. When follicles mature, some primary oocytes become secondary oocytes. By the time of ovulation there is only one mature follicle remaining. The rest of the follicles deteriorate. During ovulation (about once a month), the dominant follicle bursts and releases its secondary oocyte. The oocyte travels into the uterine tube, where it can be fertilized.
Female reproductive system terms from the Des Moines University Online Medical Terminology Course.
A guide to gynecological health from The University of Chicago School of Medicine Online Library.