The sexual and reproductive organs on the outside of a woman's body are called the external genitals. There are three openings in the genital area. In front is the urethra, from where urine comes out; below the urethra is the opening to the vagina which is called the introitus; and the third is the anus from where a bowel movement leaves the body.
The outer genital area is called the vulva. The vulva includes the clitoris, the labia majora and the labia minora. The most sensitive part of the genital area is the clitoris. This is a pea-shaped organ which is full of nerve endings and its only purpose is to provide sexual pleasure. The clitoris is protected by hood of skin, and is the equivalent of the male penis.
The labia majora or outer lips surround the opening to the vagina. They are made of fatty tissue that cushions and protects the vaginal opening between these outer lips are labia minora or inner lips these lips are sensitive to sexual stimuli. As they get stimulated, they take on a deeper colour and begin to swell.
The vagina is a muscular tunnel that connects the uterus (or womb) to the outside of the body. The vagina provides an exit for the menstrual fluid, and an entrance for the male's semen, which is ejaculated during sexual intercourse. Normally flat, like a collapsed balloon, the vagina is extremely flexible and can stretch to accommodate a tampon, a penis or even a baby's head (during childbirth)! The walls of the vagina are muscular, smooth and soft. The vagina is a closed space, which ends at the cervix.
The uterus or the wombs, is the palace where the fertilized eggs grows and develops into a baby during pregnancy. The uterus lies deep in the lower abdomen the pelvis-and is just behind the urinary bladder. The uterus is a hollow organ shaped like a pear end is about the size of the fist. Inside the muscular walls of the uterus is a very rich lining, namely the endometrium, and it is in this lining that the fertilized egg gets implanted. If, however, pregnancy does not occur, this lining is shed along with blood in the form of the menstrual flow.
The neck of the uterus is called the cervix. It connects the uterus to the vagina and contains special glands called crypts that produce mucus, which helps to keep bacteria out of the uterus. The cervical mucus also helps sperm in entering the uterus when the egg is ripe.
Two tubes, known as fallopian tubes, are attached to the upper part of the uterus on either side and are about 10 cm long. They are about as thick as a piece of noodles each tube forms a narrow passageway that opens like a funnel into the abdominal cavity, near the ovaries funnel into the abdominal cavity, near the ovaries (described later). The ends of the fallopian tubes are draped over the two ovaries and they serve as a passage for the egg to travel from the ovary into the uterus. Each fallopian tube is lined by millions of tiny hairs called cilia that beat rhythmically to propel the egg forward. Of course, the tube is not just a pathway- it performs other functions too, including nourishing the egg and the early embryo in its cavity. Also, the sperm fertilize the egg in one of the fallopian tubes.
The two almond sized ovaries are perched in the pelvis, one on each side, just within the fallopian tubes' grasp. Each month, at the time of ovulation, a mature egg is released by an ovary. This egg is "picked up" by the fimbria (a bordering fringe at the end of the fallopian tubes) and drawn into the fallopian tube. How does the egg reach the fallopian tube? When ovulation occurs, the mature egg is releases from the follicle in the ovary. This process of follicular rupture looks a bit like a small volcano erupting on the ovarian surface. At this time, the tubal fiimbria, like tentactes, sweep over the surface of the ovary and actually "swallow" the egg. The egg has a shell called teh zona pelluzida which looks somewhat like the ring of saturn.The shell is surrounded by a cluster of nest cells called the corona cells, which serve to narture the egg. These cells form the cumulus oophorus, which is a sticky gel that protects the egg and also helps the beating of the hair-like cilia of the fallopian tube to propel the egg towards the uterus-like, a conveyor belt. The egg must now wait in the protective confines of the fallopian tube, for a sperm to swim up and reach it.
The ovary contains about 2 million eggs during the sixth months of fetal life. From that point onwards, the number of eggs progressively decreases, till only about 300,000egg cells are left at the time of the birth- a lifetime's stock. During the fertile years, fewer than 500 of these eggs will be released into the fallopian tubes- once in each menstrual cycle. One of the existing eggs becomes matured for ovulation each month, and this limited supply runs out at the time of menopause. Unlike the testes in the male, which are continually, churning out billions of new sperm, the ovary never produces any new eggs.
The menstrual cycle:
The aspect of the reproductive system, of which women are most aware, is the menstrual period or menstrual flow which they have every month. The time from the beginning of one period to the beginning of the next one is known as the menstrual cycle. Usually menstrual cycles last about 28-35 days, though any time period from 3 to 6 weeks is considered normal. If pregnancy does not occur, the uterus must get rid of this thick lining so that it can grow a new one in the next cycle. The old lining passes out of the uterus through the vagina as the menstrual flow.
The menstrual flow thus consists of:

(1) The shed uterine lining;

(2) Blood (this cones from the blood vessels which are torn when the lining is shed); and

(3) The degenerated unfertilized egg.

If the menstrual flow is heavy, sometimes clots may be formed in it. Sometimes, the uterine lining is shed as large fragments and these fragments may sometimes look like bits of pregnancy tissue to some women, who may think they are miscarrying. The cycle of ovarian hormone production consists of two phases. In the first phase, called the follicular phase, estrogen plays dominant role. During this phase the egg matures inside the ovary in its follicle, which consists of: the egg; the surrounding cells (which nurture the egg and are called granulosa cell and theca cell); and the fluid (called follicular fluid) which accumulates in progressively larger amounts during this phase. The follicle secretes a large amount of estrogen (produced by the granulosa cells) into the bloodstream, and this estrogen circulates to the uterus, where it stimulates the endometrium to thicken.
The second phase of hormone production begins after ovulation, midway through the cycle, when the follicle changes into a small mass of yellow tissue called the corpus luteum. Travelling through the bloodstream to the uterus, progesterone complements the work begun by estrogen by stimulating the endometrium to mature and making it possible for fertilized egg to get implanted in it. In case pregnancy does not occur, the rate of production of estrogen and progesterone begins to fall 10 to 14 days after ovulation as the corpus luteum dies, and the endometrium is shed from the body during the menstrual period.