WOMEN’S BODIES: INTERNAL REPRODUCTIVE ORGANS DURING PUBERTY
The internal reproductive organs are the ovaries, the fallopian tubes, the uterus and the vagina.
During childhood these organs are small and inactive. This changes at puberty, when the ovaries start to mature in response to gonadotrophin hormones from the pituitary gland.
The ovaries
From before birth each ovary contains many immature egg cells (ova) resting beneath the ovarian capsule. Each ovum is surrounded by a layer of special cells, called follicular cells. An ovum and its surrounding follicular cells form an ovarian follicle.
Soon after the growth spurt of puberty, some ovarian follicles become active. Their follicular cells multiply and start producing increasing amounts of the hormone oestrogen, which is released into the blood. Oestrogen circulating in the blood affects most organs and tissues in the body, but its most profound effects are seen in the internal reproductive organs, the external genitals, the breasts and the development of female secondary sexual characteristics.
While the follicular cells are making oestrogen, some egg cells (ova) leave their resting state and begin to mature. In the early years of puberty ova don’t develop fully and are not released, but soon after regular menstrual cycles are established an egg will be released with each cycle, which means that your ovaries have reached maturity.
The fallopian tubes
Under the influence of oestrogen, the short narrow tubes of childhood lengthen and expand at the end near the uterus. The muscle in their walls increases; their lining membrane produces fluid to fill the tubes. The fimbriae at their ovarian ends enlarge and begin to move over the surface of the ovaries.
The uterus
Oestrogen stimulates the muscle in the wall of the uterus to grow so that it expands to its adult size. Oestrogen also causes a remarkable change in its lining membrane, the endometrium. The thin membrane of childhood develops into a layer about 1 cm thick, rich in glands, blood vessels and special stromal cells. The ovarian hormone progesterone also affects the endometrium. The lining of the cervix begins to produce mucus.
Around the age of 13 the endometrium starts to be shed at the end of each menstrual cycle, and regrow during the next cycle. This is menstruation.
The vagina
In childhood the vagina is a short, narrow tube with a smooth, thin lining. Once oestrogen begins to circulate, the vagina grows longer and wider and expands at the end near the uterus. The amount of muscle in its wall increases, and its lining membrane thickens and becomes folded. Clear fluid seeps from blood vessels in the lining and drains onto the vulva. This fluid keeps the vagina and vulva moist.
Many girls become worried during the development of their genitals, especially if they haven’t been warned to expect changes. If while you were growing up you have sensed an adult attitude that there is something shameful about genitals and that sexual feelings are ‘bad’, you may be quite alarmed by what is happening. Some girls may think that the anatomical changes are abnormal and have happened as a result of touching the genitals for sexual pleasure. This is never true, of course, but an understandable reaction, especially as you can no longer compare the appearance of your vulva with those of other girls; everything is now hidden by pubic hair. Even if you could, you’d find differences. The form of every woman’s genitals is slightly different -just as our faces are.
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