The human body

How do the female sex organs work?

The female sex organs make it possible for women to become pregnant and give birth to children. But they have other important jobs, too: They produce hormones, control the process of girls maturing into grown women, and make sex and sexual pleasure possible. Like men, women have external and internal sex organs.

What jobs do the external sex organs do?

The external female sex organs include:

  • Outer labia (labia majora)
  • Inner labia (labia minora)
  • Clitoris
  • Vaginal vestibule
  • Bartholin’s glands

Illustration: Female sex organs, side view – as described in the articleFemale sex organs, side view

The external sex organs allow for sexual intercourse and sexual pleasure. The skin and mucous membranes on the external sex organs – especially on the head (glans) of the clitoris, the inner labia and the vaginal vestibule – have a lot of nerves and are very sensitive. As a result, touching and rubbing this area can cause sexual arousal and increased pleasure that may lead to orgasm.

The structures of the female clitoris and the male penis are similar because they develop from the same organ when the baby starts growing in the womb. The clitoris is mostly inside the body, and reaches from a joint in the middle of the pelvis (the pubic symphysis) to the front wall of the vagina. It consists of the head of the clitoris with a foreskin (clitoral hood), as well as the shaft and two “legs” with erectile structures (corpora cavernosa) that are positioned to the left and right of the urethra. Only the head of the clitoris, the hood and – during sexual arousal – part of the shaft are visible from the outside.

The corpora cavernosa of the clitoris and of the vaginal vestibule are made of a sponge-like tissue. During sexual arousal, blood builds up in the corpora cavernosa until they are full and firm. This also causes the head and shaft of the clitoris to swell and stiffen. During an orgasm, the muscles beneath contract (tense) rhythmically.

As soon as a woman is sexually aroused, the small Bartholin’s glands at the opening of the vagina release a fluid. The vagina becomes moist, making it easier for the penis to enter during sex.

What jobs do the internal sex organs do?

The main jobs of the internal female sex organs are to enable pregnancy and childbirth. The internal sex organs include:

  • Ovaries
  • Fallopian tubes
  • Uterus (womb)
  • Cervix
  • VaginaIllustration: Internal female sex organs, front view – as described in the articleInternal female sex organs, front view

The two ovaries are the female reproductive glands (gonads). They are located on the right and left sides of the abdomen, and contain the eggs. These eggs can be fertilized by male sperm. The ovaries also produce important female sex hormones such as estrogen and progesterone, which – among other things – regulate the menstrual cycle.

The fallopian tubes connect the ovaries to the uterus: During ovulation, one of the ovaries releases a mature egg into the funnel-shaped entrance of the fallopian tube. The egg then travels through the fallopian tube to the uterus. After sex, the egg can already be reached and fertilized by a sperm cell in the fallopian tube.

The uterus (womb) is roughly pear-shaped, and held in place in the pelvis by ligaments and muscles. The two fallopian tubes enter the upper, rounded end of the uterus on the right and the left. The lower part of the uterus is somewhat narrower, resembling the neck of a bottle. This section is called the cervix. The very bottom end of the cervix bulges into the vagina a little, at the opening of the cervix. On the infertile days of the menstrual cycle, the opening of the cervix is closed by thick mucus.

The inside of the uterus is lined with special membranes called the endometrium. In each menstrual cycle, female sex hormones stimulate the endometrium to grow into a thick layer with higher blood flow so it is prepared for a fertilized egg: The egg can then become implanted in the lining of the uterus and grow into an embryo. If fertilization doesn't take place, the thick membrane tissue which has built up is shed and leaves the woman's body during her period.

During pregnancy, the uterus stretches to accommodate the growing baby. Shortly before and during childbirth, the uterine muscles repeatedly contract strongly. These contractions help to push the baby outwards through the vagina.

The vagina connects the internal and external sex organs. It receives the penis during sexual intercourse. At its upper end, the cervix provides an entrance for male sperm cells to reach the uterus – and during childbirth, it’s the passageway for the baby.

What possible problems can occur?

Various problems may occur if female sex organs change or are affected by medical conditions:

  • Pain and cramps, for instance before or during periods, only during sex, or all the time
  • Itching, red skin and swelling
  • Discharge, burning sensation when urinating (peeing)
  • Bleeding
  • Vaginal dryness
  • Infertility
  • Hormonal imbalances

In general, problems in the genital area can be caused by many different things, such as viral, bacterial or fungal infections. Typical examples include vaginal infections (vaginosis), herpes, genital warts or inflammations of the fallopian tubes and uterus due to a sexually transmitted infection like gonorrhea. The fallopian tubes can then become stuck together, preventing egg cells from passing through them.

Developmental disorders, malformations or changes to the organs may also occur. In some women, for example, the kind of tissue that lines the uterus grows elsewhere in the body too – usually in the abdominal cavity (endometriosis). This can cause severe abdominal pain. The uterus can also slip down into the vagina (uterine prolapse), especially in older women.

Single or multiple hollow sacs (cysts) may develop in the ovaries. These are often filled with blood. Bleeding can also occur in the fallopian tubes or in the ligaments that hold the uterus in place in the pelvis. If the ligaments become twisted, it can affect the supply of blood to the fallopian tubes or ovaries.

Non-cancerous growths known as fibroids are especially common in the muscles of the uterus. Cancerous growths in the female sex organs most commonly affect the uterus, cervix, ovaries and the skin in the pubic and vaginal area. Cervical cancer often develops from abnormal changes in the mucous membrane cells (dysplasia), making the cells multiply faster. Dyplasia on the cervix is referred to as cervical intraepithelial neoplasia (CIN). It can also occur on the external sex organs such as the vulva (VIN) or in the lining of the vagina (VAIN).