The reproductive system in women is made up of external and internal organs.
These are found in the lower abdomen, the part of the body below the umbilicus (bellybutton). This area is often referred to as the pelvic area. The sexual organs include:
The Female Reproductive Organs Outside the Body
The vulva includes the opening to the vagina, the inner and outer lips (called labia) and the clitoris. The external part of the clitoris is found towards the front of the vulva. It is highly sensitive and when stimulated can make women feel sexually aroused, leading to an orgasm.
Hormones and Eggs
– Do you Know?
- The female sex hormones, oestrogen and progesterone, are responsible for female characteristics such as body shape, developing breasts, and controlling the menstrual cycle.
- When a woman reaches puberty she will have up to one million eggs in her ovaries.
- During a woman’s reproductive lifecycle only about 400-500 eggs will actually be released at ovulation.
- As a woman gets older (over 30 years) the number and quality of her eggs declines making conception more difficult.
- An egg is less than 1/8 of the size of a grain of sand – invisible to the naked eye.
The Female Reproductive Organs Inside the Body
Women have two ovaries, one on each side of the uterus. Ovaries are the size and shape of almonds and they contain ova (eggs) in structures called follicles. The ovaries also produce the two female sex hormones – oestrogen and progesterone. When one does not want to fall pregnant, a morning after pill will prevent any eggs from being released by the ovaries.
The Fallopian Tubes
The two fallopian tubes are found on each side of the uterus, near the ovaries. These are tiny tubes – only as wide inside as a strand of human hair and just 10cm long! The funnel-like ends of the fallopian tubes pick up the egg released by the ovary, unless using contraception, and carry it to the uterus. Tiny, microscopic hairs line the inside of the fallopian tubes and help move the egg along. The inside of the tube is very delicate and can very easily be damaged or blocked by infection.
The uterus is made of muscle. It’s about the size and shape of an upside down pear, and is hollow and very stretchy. This is where the baby develops if a woman becomes pregnant. The uterus can stretch to hold a baby and shrink more or less back to its pre-pregnancy size after the birth of a baby.
The lower part of the uterus connected to the vagina is called the cervix. Sperm released by the man during sex, will swim from the vagina through the cervix to reach an egg.
The cervix contains small glands which produce secretions called mucus. This alters in texture and amount during a woman’s menstrual cycle. In her fertile phase (the time around ovulation when an ovary releases an egg), it changes from being thick, sticky and creamy in colour to being clearer, wetter, and more stretchy – like raw egg white. These changes allow sperm to pass through the cervix and reach the egg more easily. When a woman is pregnant, the cervix becomes plugged with very thick mucus to protect the developing baby from infection.
The vagina is a muscular tube, 7 – 10cm long which leads from the cervix to the vaginal opening (vulva).The vaginal opening is between the legs, between the urethra (where a woman urinates from) at the front and the anus at the back. The vagina tilts upward and towards the small of the back. It has glands which produce lubricating secretions when women are sexually aroused to help the penis enter the vagina (penetration). Like the uterus, the vaginal walls are stretchy, allowing it to hold a tampon and stretch around a penis during sex, or a baby during birth.
The Menstrual Cycle
- The menstrual cycle is the process during which an egg develops and is released from the ovaries, and the lining of the uterus prepares for a possible pregnancy. If a woman does not become pregnant the lining of the uterus is shed, as her period.
- These events are caused by hormones – chemical messengers which travel around the body in the blood stream.
How long does the cycle take?
- The number of days in the menstrual cycle is calculated from the first day of a woman’s period to the day before the start of the next period.
- The average length of the menstrual cycle is around 28 days, although many women have longer or shorter cycles, which is normal.
What happens during the menstrual cycle?
- The first day of the period is known as day one of the cycle. When a woman has her period, about 20 eggs start to develop in the ovary.
- The hormone, oestrogen, causes the lining of the uterus (endometrium) to start thickening in preparation for a fertilised egg. It also causes the mucus in the cervix to become thinner, wetter and stretchier, allowing sperm to reach an egg more easily.
- Regardless of how long or short a woman’s cycle is, ovulation (the egg being released from an ovary) will usually happen around 10 – 16 days before the start of her next period. However, the time from the first day of the period to ovulation can vary between women.
- Occasionally, more than one egg is released (if this happens it will occur within 24 hours of the first egg being released). If more than one egg is fertilised it can lead to a multiple pregnancy (twins).
- Ovulation triggers the production of the second hormone, progesterone. This prepares the lining of the uterus even further, ensuring that it is spongy, thick, and full of nutrients so that a fertilised egg can settle or implant into it.
- After ovulation, the cervical mucus goes back to being thick and sticky. If the egg is not fertilised it will be reabsorbed naturally by the body, the level of hormones fall, and this menstrual cycle comes to an end. The cycle then begins again. The lining of the uterus breaks down and is shed through the vagina as a period, also called menstruation.
Periods – Do you Know?
- Some menstrual cycles can be as short as 21 days and some as long as 40 days.
- Some women have menstrual cycles that vary in length from month to month.
- The amount and quality of cervical secretions will vary from woman to woman and also from one cycle to the next.
- The average amount of menstrual blood lost in one period is three – five tablespoons.
- A period usually lasts between 3 – 7 days.
- Women living together often find that they have their periods at the same time.
- Some women have pain around ovulation called Mittelschmerz – this means, middle pain.
Reproduced with kind permission from www.fpa.org.uk