The female reproductive system

Located in the pelvic region, the female reproductive system consists of two ovaries and two oviducts, the uterus, cervix and vagina, and the external genitalia; a pair of mammary glands is functionally linked to it.

Ligaments hold each ovary, about 2–4 cm long, to the pelvic wall and the uterus. A thin epithelium covers it, and inside lies the ovarian stroma, with an outer cortex and an inner medulla. The ovaries produce ova as well as several steroid hormones.

Each oviduct (fallopian tube) measures about 10–12 cm. The funnel-shaped infundibulum lies nearest the ovary, and its finger-like fimbriae help collect the released ovum; next comes a wider ampulla, and last a narrow isthmus that joins the uterus.

The uterus (womb) is a single organ shaped like an inverted pear and held to the pelvic wall by ligaments. It opens into the vagina through a narrow cervix; the cervical canal together with the vagina forms the birth canal.

The uterine wall has three layers: the outer thin perimetrium, the thick middle myometrium of smooth muscle that contracts strongly during childbirth, and the inner glandular endometrium that lines the cavity and changes cyclically during the menstrual cycle.

The external genitalia are the labia majora, labia minora, mons pubis, clitoris and hymen. Above the urethral opening lies the clitoris, a small finger-like structure.

The hymen partly covers the vaginal opening. It can tear during a fall, a sudden jolt, insertion of a tampon, active sport such as horse riding or cycling, or first intercourse, and in some women it persists after intercourse, so it is not a reliable sign of virginity.

The breasts are paired mammary glands made of glandular tissue with a variable amount of fat. In each breast the glandular tissue is split into 15–20 mammary lobes, and each lobe has clusters of milk-secreting cells called alveoli.

Milk made in the alveoli flows along this route: alveoli → mammary tubules → mammary duct → wider mammary ampulla → lactiferous duct, which opens at the nipple.