ovaries

The ovaries are small, oval-shaped organs, which are located just below the Fallopian tubes on either side of the womb (uterus). The ovaries contain fluid-filled bubbles or follicles that in turn contain immature, or unripe, egg cells (ova). All these egg cells were produced by the woman when she was a foetus. Yet only a fraction of them will actually develop into mature, or ripe, ova during her life. After puberty, many ova will start the development process each month, although usually only one will be released or ovulated each month. After ovulation, the ovum enters the Fallopian tubes.

fallopian tubes (oviducts)

The Fallopian tube is the site of fertilisation. While the Fallopian tube appears to be a simple organ, it is actually quite complex. Each tube has fan-shaped ends or fingers, the so-called fimbriae, which brush along the ovary and collect the ovulated egg (ovum). The Fallopian tube, which has a circumference of almost 1¾ centimetre at the open end near the ovary, narrows when it approaches the womb to the diameter of a pencil tip. The end closest to the ovary constricts in order to push the ovum down to the site of fertilisation, while the end that is closest to the womb pulls itself up in order to aid the passage of sperm along the tube. Throughout the process of fertilisation, the Fallopian tube creates the ‘right’ environment to maintain the female ovum and the male sperm. It can take some days for the ovum and subsequently the embryo (fertilized egg) to negotiate the length of the Fallopian tube and reach the womb.

The Fallopian tubes have the following tasks:

• Picking up the released ovum (egg).
• Providing sustenance and movement for the ovum.
• Transporting sperm to the ovum.
• Creating the “right” environment for fertilisation.
• Transferring the embryo (fertilised ovum) to the womb.

womb (uterus)

The womb is a hollow, pear-shaped organ, situated low in the female pelvis. It is often referred to as the uterus. After ovulation (egg release), the lining of the womb grows in anticipation of receiving an embryo (fertilised egg) from the Fallopian tube. Following successful implantation, it protects, develops and feeds the foetus until birth. If a woman is not pregnant, then the lining of the womb – known as the endometrum - is shed when she begins her menstruation (period).

cervix (cervix uteri)

The cervix is the connection between the lower part of the womb and the vagina. It produces mucus like secretions that change during the reproductive cycle both in terms of the amount produced and its composition. During the woman’s fertile days around the time of ovulation, the cervical mucus is thin and watery in order to aid the passage of sperm into the womb. After ovulation and/or during pregnancy, the cervical mucus thickens to form a protective barrier against foreign substances and infections.

An increase in healthy vaginal secretion halfway through the cycle can be an indication of the approaching ovulation.

standard female reproductive physiology

The monthly cycle of a woman is a complex process involving a great many organs and hormones.

To begin with, on the first day of menstruation (day 1 of a woman’s cycle), the body starts to produce and release ever-increasing amounts of follicle stimulating hormone (FSH). This hormone, produced by the pituitary gland at the base of the brain, ensures that the follicles grow and produce oestrogen, the female hormone. At that point, the eggs developing inside some of the follicles begin to ripen, or mature. During the average cycle, on day 14, the pituitary gland releases a large amount of yet another hormone, called luteinizing hormone (LH); this is called the LH-peak. LH stimulates the ultimate maturation of one egg and starts the ovulation process – the release of a mature egg by the dominant follicle and the ovary. During the time that the released egg moves through the Fallopian tube, the ovulated follicle produces levels of another hormone, called progesterone. Progesterone instructs the lining of the womb to prepare for the implantation of a fertilised egg (embryo).

The first half of the cycle (in which the follicles mature) is called the follicular phase; the second half is referred to as the luteal phase.

If sperm cells are present in the Fallopian tube, the egg (ovum) can be fertilised and the resulting embryo moves down the Fallopian tube to the womb, where it can implant and hopefully grow into a baby. In the event that the ovum is not fertilised, it still moves towards the womb, but is unable to implant and simply degenerates. Approximately two weeks after ovulation, the non-pregnant womb sends a signal to the ovary to decrease progesterone production. As a result, the lining of the womb is shed and released through menstruation. The whole cycle then begins once again.