The vulva consists of the female's external sex organs
The main biologic roles of the female genitalia include passing urine, giving birth, sex and excreting menstrual fluids. The vagina develops in several phases, mostly during fetal and pubertal stages. The external "labia majora" and internal "labia minora" are double "doors" that protect the openings of the vagina and urethra. The clitoris is in the front of the vulva. The vulva, especially the clitoris, is much richer in nerve endings compared to other organs of the body, and that is why it is so sensitive to pain and pleasure (which was designed that way biologically to be an incentive to have sexual activity).
The soft mass of fatty tissue that covers the pubic bone is the mons pubis. At the end it divides into the labia majora on the sides of both folds of skin. The color of the labia majora is usually the same as the woman's skin, however, sometimes there are noticeable differences. The inner skin and mucous membrane are usually a shade of pink or brown. At the onset of puberty, the mons pubis gets covered with pubic hair. The hair usually grows in the direction of the thighs and perineum, but with a lesser degree of density.
The labia minora are two soft flaps of skin inside the labia majora. Even though it is called the "labia minora", at times they can be quite large and even protrude outside the labia majora. The main difference between women's vulvas lies in the significant variety of sizes, shape, and color of the internal lips.
The Clitoris is found in the vulva and made up of erectile tissue with thousands of nerve endings. During sexual arousal, the clitoris engorges, becomes sensitive to touch, and transfers excitement and sexual pleasure which may lead to an orgasm. The clitoris is a sex organ that exists only in female mammals. The clitoris of human females is visible to the eye and is located close to the area of the labia minora, above the urethral opening and the opening of the vagina. The clitoris is composed of spongy, erectile and phalangeal tissue. This is an organ that is primarily internal and spans at the base of the female's pelvis. The clitoris is meant for pleasure only and has no other function.
The urethra and bladder
The bladder is a muscular organ that resembles a sac, located in the pelvis and stores the filtered urine from the blood in the kidneys. The urine reaches the bladder from the ureters leaving the kidneys. Release of urine from the bladder is controlled by a valve located at the top of the urethra. It is only 3-4 centimeters long for women, and does not pass through any sexual organs (unlike in men, where the urethra passes through the penis). It ends at the urethral opening in the vulva and is located between the clitoris and the vagina.
Sexual arousal causes several physical changes in the vulva
It is possible to divide arousal to roughly four arbitrary stages:
First, the vulva is lubricated by the walls of the vagina due to the concentration of blood that causes moisture to permeate from the walls. These drops are gathered and begin to flow outside the vagina, wetting the vulva. The labia majora flatten and spread. The clitoris and labia minora grow. Unlike men, where it is easy to identify sexual arousal (because of an erection), women are not necessarily aware and therefore their vulva becomes lubricated.
An increase in the density of the blood supply to the vulva causes it to engorge, and as a result the vaginal opening decreases by approximately 30%. The clitoris becomes more erect and the hood moves away, towards the pubic bone, so that it is concealed by the glans. The width of the lips increases to up to 2-3 times of their original size. This thickening causes them to spread and thus exposes the opening of the vagina.
Right before the orgasm, the clitoris engorges and causes the hood to come off of the glans. Muscle contractions occur in the vagina, uterus and rectum. At first, these contractions occur at a pace of every 0.8 seconds. During an orgasm, they weaken and become more sporadic. The number of contractions depends on the intensity of the orgasm. An orgasm may be accompanied by female ejaculation, fluid whose source is from the skin glands or bladder. Immediately after an orgasm, the clitoris may be very sensitive to the point that additional stimulation may not be arousing or comfortable.
The blood that accumulated in the vaginal wall begins to dissipate. If there was no orgasm then it does so at a slower pace. The vulva returns to its normal state.
The vagina is a muscular and flexible tubular part that connects the vulva's walls to the cervix. The vaginal opening is located at the lower posterior end of the vulva, under the opening of the urethra. The vagina is the organ penetrated by the penis during intercourse and into which the semen is ejaculated. The sperm cells pass through the vagina to the cervix and from there to the uterus and the fallopian tubes where the fertilization of a woman's egg takes place and where pregnancy begins. The fertilized egg moves from the fallopian tube into the uterus and attaches itself to the lining of the uterus. The embryo then develops in the uterus until birth.
During childbirth, the elastic walls of the vagina expand in a manner that allows the fetus to move from the uterus outside the woman's body. In this context, the vagina is referred to as the "birth canal". Menstrual fluids (monthly menstruation) are also excreted through the vagina when pregnancy did not happen after ovulation. The length, width and shape of the vagina change during the course of a woman's life. During intercourse or childbirth, the vagina expands to about two or three times its original size. A vaginal lubricant (which gives the feeling of internal moistness) is secreted during sexual arousal by glands located near the opening of the vulva and the cervix. The vaginal walls also secrete a lubricant even though they do not have any glands.
The Hymen – is located behind the opening of the vagina and for most women it partially covers the vagina from birth until it is torn during the first sexual intercourse, or as a result of injury, a medical examination, intensive physical activity, using a tampon or menstrual cup.
The vagina can also be a source of sexual arousal for women, yet there are those who maintain that vaginal orgasms are less intense than orgasms from clitoral stimulation. The vagina has an area known as the "g-spot". There are women who have orgasms and intense sexual arousal from contact with the g-spot.
The G-Spot – or the Gräfenberg spot, named after the German gynecologist, Ernst Gräfenberg, is a small part in the woman's body located up at the front of the vaginal wall, behind the pubic bone and around the urethra. It is widely believed to be an erogenous zone that when stimulated it leads to strong sexual pleasure and intense orgasms. The mere existence of the g-spot is controversial, and majority of books relating to it are designated for the general public and are not scientific. The term "g-spot" was coined in 1981 by Frank Addiego, an American sexologist, after Gräfenberg, who assumed this spot existed in the 1950's.
The Cervix is the narrow and lowest part of the uterus. The cervix connects the uterus and the vagina. The lower part of the uterus protrudes into the vagina and thus it can be seen in a gynecological examination.
The Cervix' Roles
During an orgasm, the cervix moves and the external orifice expands. Initial studies suggest that the cervix acts in such a manner that draws the ejaculated semen located in the vagina into the uterus and therefore increases the chances of fertilization.
During monthly menstruation the opening of the cervix slightly widens to allow the uterine lining to shed through it. There are those who believe that menstrual cramps partially derive from this widening. To support this claim, it is notable that the pain from cramps during a woman’s period decreases in its intensity and even disappears after the first childbirth, probably because the opening of the cervix widens.
During childbirth, the uterine contractions cause the cervix to expand to a diameter of approximately 10 cm, in order to allow the baby to pass through it.
General – Female Reproductive Organs
Humans belong to the mammalian class since their fetus grows in the woman's uterus until birth then suckles upon birth. A woman has two ovaries where ova (eggs) develop. Near the ovaries are the fallopian tubes through which the eggs pass from the ovaries to the uterus. The vagina, a broad tubular part, connects between the uterus and the vulva, which is the gamut of a female's external sex organs.
The Uterus is a muscular and tubular organ with thick walls located in a woman's body that allows for the development of a fetus inside it. The uterus is hollow, pear shaped, and located in the pelvic area. The two fallopian tubes connect to the upper part of the uterus and to the ovaries. The lower part of the uterus, the cervix, which is a strong, ring like muscle, connects to the vagina. The vagina is the part that connects the internal reproductive organs to the external world and serves as internal passage for the sperm cells and as an external canal for childbirth.
The ovaries are located in the lower abdominal region, above the uterus, and their function is to create ova (eggs), which are reproductive cells (sperm cells are the reproductive cells in men). The eggs move from the ovaries to the fallopian tubes where they wait a short time to be fertilized, in other words, receive the male reproductive cells and continue on their way to the uterus. If an egg is fertilized by a sperm cell, it attaches itself to the uterine wall, developing into an embryo. This is the process we call pregnancy. If fertilization does not occur – which is the usual situation – then the egg dies and is expelled outside the body together with the uterine lining that was preparing for its implantation. This process is known as menstruation (monthly period).
During puberty, the eggs mature and begin to be released – one egg every 28 days – into the uterus. The monthly period stops when a woman reaches menopause, that is, when she can no longer become pregnant (because the maturation and release of eggs stops – although there are more than a thousand eggs that never matured in her ovaries).
In addition to producing eggs, several female hormones are synthesized in the ovaries (estrogen, progesterone, etc.). These compounds are sent from the ovaries, through the blood vessels, to all parts of the body, causing physiological changes characterizing the differences between men and women (for men the male hormones are produced in the testes).
The Fallopian Tubes
The fallopian tubes are two tubes that connect between the ovaries and the uterus. The tubes, are each connected on one side to a different side of the upper part of the uterus and on their other side, to one of the ovaries. The fallopian tubes are not directly connected to the ovaries but open onto them. When an egg is produced in the ovary, it is enclosed in a sac known as the "ovarian follicle". When the egg is ready, the ovary wall and follicle rupture and it is released into the fallopian tube where it makes its way to the uterus, by being pushed forward with the help of the motility of the cilia, which is in the internal coating of the fallopian tubes. The journey into the utrus is a few hours or a few days long (this is ovulation). If the egg is fertilized by sperm when it is in the fallopian tube, then it usually attaches itself to the uterine wall, indicating the onset of pregnancy. At times, a fertilized egg attaches to the fallopian tube and not the uterus, causing what is known as an ectopic pregnancy.
The Anus is the external opening of the rectum, which is at the end of the large intestine. It opens and closes by two ring-like muscle sphincters through which stool is excreted from the digestive system. The coating of the anal duct can be easily bruised by hard stool. The duct is padded by a mucous membrane. The skin of the anus contains milk and sweat glands.
The anus also has a role in human sexuality. During anal sex, the male penis (or a sex toy) penetrates the anus into the rectum, thus stimulating the nerve ends of the vagina for women or the prostate for men, which are close to the back end of the rectum.
The rectum is the end part of the large intestine. This is an organ that is duct-like and whose length is 17 centimeters. It is connected to the anus through a small duct called the anal duct. As the last organ of the digestive system, the rectum serves to collect and store waste created in the large intestine until it is excreted from the body in the form of stool.