REPROSAIT 4 U

New life begins when an egg from a woman is fertilised by sperm from a man. Eggs (ova) are made in the ovaries, and sperm in the testicles. The ovaries and testicles (gonads) also make sex hormones.

The female reproductive system

The female reproductive system is made up of the vagina, womb (uterus), fallopian tubes and ovaries.

1. VAGINA - a muscular canal around 7.5 cm long that extends from the neck of the womb to the genitals, or vulva.
2. UTERUS (womb) - a muscular organ, shaped like an upside down pear. Its lining is called the endometrium. The neck, or entrance to the womb is the cervix, which has a small hole in its centre, called the os.
3. FALLOPIAN (uterine) TUBES - these tubes extend from the womb, one on each side. They both open near an ovary. These tubes carry the egg (ovum) from the ovary to the womb.
4. OVARIES - two small almond shaped glands that contain eggs (ova). Sex hormones (oestrogen and progesteron ) are also made by the ovaries.

The menstrual cycle

Hormones secreted by the ovaries (oesterogen and progesteron ) and a small gland in the brain called the pituitary gland ( folicle stimulating hormon – FSH and luteinizing hormon – LH ) control the menstrual cycle.

The average cycle is around 28 days. After a period, rising levels of the hormone oestrogen help to thicken the lining of the womb (the endometrium).

At mid-cycle, an egg is released from one of the ovaries (ovulation).

If the egg is fertilised on its journey down the fallopian tube, it lodges in the womb lining. If the egg is unfertilised, falling levels of the hormone progesterone make the womb lining come away. This is called a period, or menstruation. The cycle then repeats.

The ovum (egg)

A female’s entire egg supply is developed when she is still an unborn baby. At the start of puberty, the eggs or ova are ripened inside the ovary and released every month. Each egg contains genetic material. At menopause, the ovaries stop making hormones and eggs are no longer ripened or released.

Mammary gland

Mammary gland organ of the female mammal that produces and secretes milk for the nourishment of the young.

A mammal may have from 1 to 11 pairs of mammary glands, depending on the species.

Generally, those mammals that bear larger litters have more glands. The mammary gland of the cow and of some other mammals is known as the udder.
In humans, there is one pair of mammary glands, also known as mammae, or breasts. They are rudimentary in both sexes until the age of puberty when, in response to ovarian hormones, they begin to develop in the female. During pregnancy, they distend still further in preparation for nursing the infant. Pregnant women are prevented from lactating (producing milk) by the presence in the blood of high levels of estrogen and progesterone , secreted by the placenta until birth occurs.
After birth, response to prolactin, the milk-stimulating hormone, , is no longer inhibited by placental hormones, and lactation begins. Mammary tissue contains between 15 and 20 compartments called lobes, each of which is divided into smaller compartments called lobules. The lobes and lobules are connected by a network of tubes whose cells manufacture the liquid and fatty substances that form milk. The tubes of each lobe connect with a duct, and all ducts lead to the nipple, where the milk is secreted when the nipple is sucked by the young. The letdown of milk during the nursing process is aided by oxytocin , a hormone secreted by the pituitary. The physical force of an infant's sucking on the breast is a major stimulus to milk production. Disorders of the mammary gland include mastitis and breast cancer .

The male reproductive system

The male reproductive system is made up of the penis, the testicles, the epididymis, the vas deferens and the prostate gland.

• Penis - has special erectile tissue that can fill with blood and make the penis stiffen. Sperm leaves the penis through the urethra, the same tube used for urination.
• The testicles (testes) - small oval sex glands located in a skin sack called the scrotum. Sperm and sex hormones are made by the testicles. Keeping the testicles outside of the body means they have a lower temperature, which is important for sperm production.
• Epididymis - a series of small tubes attached to the back of each testicle. The epididymis collects and stores sperm.
• Vas deferens - the epididymis tubes connect to make the vas deferens, a larger tube.
• Prostate gland - along with the seminal vesicles, adds fluid to the sperm.

The sperm

The sperm is the male reproductive cell. Its role is to fertilise an egg (ovum) and it contains genetic material. A sperm is tadpole shaped and around 60 microns in length (one micron is a millionth of a metre). It has a lashing tail, which helps it to ‘swim’ towards a waiting egg.

Common problems

Some common problems of the reproductive system include:

For women:

• Endometriosis - problems with the womb lining.
• Fibroids - non-malignant tumours of the womb.
• Infertility - many causes, including a failure to ovulate.
• Painful periods - a number of different causes, such as inflammation.
• Premenstrual tension - symptoms include bloating, breast tenderness and mood swings.
• Sexually transmitted disease - can be caused by bacteria or viruses.

• Impotence - a problem with getting or keeping an erection
• Infertility - many causes, including low sperm production
• Prostate problems - can make urination difficult
• Sexually transmitted disease - caused by bacteria or viruses.