Sometimes, a small sample of tissue may be taken with small tools inserted through the vagina during a transvaginal ultrasound. In all three types of pelvic ultrasound, the transducer sends the reflected sound waves to a computer, which makes them into a picture that is shown on a video screen.
So the number of egg-containing follicles remaining in the ovary undergoes a steady decline from an average of 400,000 eggs at age eighteen to an average of 25,000 eggs by age thirty-seven. After age thirtyseven or thirty-eight, there is then a very dramatic acceleration of the monthly decline of remaining eggs.
What are the ovaries and what is their function? Women normally have two ovaries that store and release eggs. Each ovary is about the size of a walnut, and one ovary is located on each side of the uterus. One ovary releases an egg each month, and this process is called ovulation. Ovulation occurs in roughly the middle of a woman's monthly menstrual cycle. The egg is enclosed in a sac called a follicle.