The female genital system

• Consists of two ovaries, two oviducts (Fallopian tubes), the uterus and the vagina.
• It produces the ova and the female sex hormones and provides a safe place for the completion of fertilisation and the development of the embryo until birth.
• The organs lie behind the urinary bladder in the pelvis, held in place by elastic ligaments which allow expansion in pregnancy.

1. The two ovaries. Almond-sized, oval, lying in the sides of the pelvic cavity. In childhood each ovary has several thousand (about 200,000–400,000 by puberty) ova in different stages; after maturity only about 400 will mature during the roughly 30 years of reproductive life. One ovum is released each month, alternately from each ovary. They secrete the hormones oestrogen and progesterone that regulate the menstrual cycle and the embryo's development.
2. The two Fallopian tubes (oviducts). Each has a funnel-shaped opening with finger-like fimbriae near the ovary to receive the ovum; the lining has cilia that sweep the ovum toward the uterus (aided by muscular contractions). Fertilisation takes place in the upper (anterior/outer) third of the tube.
3. The uterus. An elastic, muscular, pear-like organ in the pelvic cavity with a thick muscular wall, lined with a glandular membrane, the endometrium; its lower end is the cervix, which opens into the vagina. The embryo grows here for nine months.
4. The vagina. A muscular tube about 7 cm long, from the cervix to the genital opening, lined with a glandular membrane that secretes mucus; folds allow expansion at birth; it receives the sperms at mating and is the birth canal.

Puberty and menopause:

• from age 12–15 years rhythmic monthly changes begin in the ovaries and uterus, either leading to pregnancy or, if no pregnancy, to monthly bleeding (menstruation).
• At about 45–50 years the ovaries become inactive (hormone secretion decreases) and the uterine lining thins: this is menopause.

Section in the ovary: shows follicles in different stages — primordial, growing and the Graafian follicle containing the ovum — and the corpus luteum formed from the follicle after ovulation.