Full Uterus and Ovaries Description
[Continued from above] . . . under the influence of hormones from the ovary. When the hormones withdraw after the menstrual cycle, the blood supply is cut off and the tissues and unfertilized egg are shed as waste. During pregnancy, the uterus stretches from three to four inches in length to a size which will accommodate a growing baby. During this time, the muscular walls of the uterus increase from two to three ounces to about two pounds; at birth, these powerful muscles release the baby through the birth canal with great force. The womb shrinks back to half its pregnant weight before a baby is a week old. By the time the baby is a month old, the uterus may be as small as when the egg first entered.
The ovaries are a pair of oval or almond-shaped glands which lie on either side of the uterus and just below the opening to the fallopian tubes. In addition to producing eggs, or ova, the ovaries produce the female sex hormones estrogen and progesterone. Unlike males, females do not manufacture the sex cells. A girl baby is born with about 60,000 ova, which are contained in sac-like depressions in the ovaries. Each of these cells may have the potential to mature for fertilization, but in actuality only about 400 ripen during the woman's lifetime.