Anatomy of the female reproductive system

What does the female reproductive system consist of?

The female reproductive system consists of the external and the internal genitalia. The external genital organs are visible outside the body and begin to mature when a girl reaches puberty. The internal genitalia are the organs where fertilisation and conception takes place.

The external genitalia

The vulva : The area starting below the navel and consisting of the external genitalia is called the vulva. The skin of the area is covered with pubic hair which begins to grow around 12 years of age. The vulva includes the following organs:

• The labia majora – literally meaning "large lips". The labia majora are two folds of skin that flap over the other external genitalia. This skin has sweat glands and other specialised glands which produce a characteristic smell. They are covered with pubic hair.
• The labia minora – meaning "small lips". These structures lie within the labia majora and flank the opening of the vagina and the urethra. They have some erectile tissue which makes them sensitive to touch. At the upper end, they unite to form prepuce to cover the clitoris.
• The clitoris – this is the structure analogous to the penis in the male. It is the most sensitive genital structure in the female and is covered by the prepuce. It has a rich supply of blood vessels and nerve endings. When adequate stimulation is provided, it becomes erect. The area around it becomes thick and bulbous due to a rush of blood.
• Bartholin's gland – this gland is located inside the vaginal opening, behind the labia minora. It is imperceptible when healthy and produces a thin mucus that provides lubrication to the vaginal opening during sexual stimulation.
• The hymen – the 'maidenhead' is a membrane composed of connective tissue that forms a tight ring around the vaginal opening. The hymen is an elastic structure that in some cases, completely covers the vaginal opening. It gets torn during the first sexual intercourse. However, it is not a reliable parameter of virginity since it is elastic might not be torn all through a woman's life. It may also get torn during other physically strenuous activities.

The internal reproductive organs

The vagina: The vagina is a muscular canal that connects the external organs with the uterus. Its average length is about 10 cm, but only the outer one third of it is sexually responsive. The upper end of the vagina, adjoining the uterus, is the cervix. The vagina does not have any glands and it is kept moist by the lubrication provided by the cervical and uterine glands. During a woman's reproductive years, the lining of the vagina seems irregular and somewhat corrugated. Before puberty and after menopause, the lining becomes smooth due to a lack of hormone production. The vagina is naturally protected against infections due to lactic acid secretion after puberty.

The uterus: The uterus is a pear shaped organ, weighing about 70 gm and is approximately 7.5 cm long in an adult female. It has thick muscular walls with a rich supply of blood vessels. The embryo, during conception, implants itself in the uterine cavity and grows there. At the upper end, the uterus opens out into the Fallopian tubes, while the lower end continues into the cervix. The lining of the uterus is made up of epithelial cells and is called the endometrium. The cells of the endometrium are shed during menstrual periods. When a woman is pregnant, the endometrium is engorged with blood and provides a cushion for the growing baby.

The Fallopian tubes: The Fallopian tubes, also called the uterine tubes, connect the ovaries with the uterus. They are about 10 cm in length and 8 mm in diameter. The fertilised egg moves down the Fallopian tubes to the uterus where it becomes implanted. The lining of the tubes has cilia or hair like structures that move and propel the egg towards the uterus.

The ovaries: The ovaries are two almond shaped organs that produce ova or eggs during ovulation. They are small in children, but begin to grow during puberty due to changes in the hormonal profile. The cells of the ovaries form a mass known as a follicle. The follicle continues to grow during a menstrual cycle and on the 14th day of the cycle, the egg is released from this follicle. Though many follicles ripen at the same time, usually only one of them matures enough to release the ovum. The egg is then released into the Fallopian tubes from where it travels towards the uterus. If it is fertilised by a sperm on the way, pregnancy results. Otherwise, the ovum degenerates and is expelled with the menstrual blood.

The sex hormones

All the changes that occur in a woman's reproductive system during puberty are, to a large extent, determined by the changes in the hormonal profile. The two main female hormones, produced by the ovaries – oestrogen and progesterone, begin to have a sexually maturational effect at the time of puberty. When the pubertal growth spurt occurs, the brain sends signals to the hypothalamus, a gland in the brain, and the ovaries to start producing the female hormones.

Sex hormones are responsible are responsible not only for the maturation of the primary sexual organs, but also for the production of secondary sexual characteristics like formation of body hair, growth of breasts, changes in voice and deposition of fat in the body.