The Vagina

The vagina is the female internal sex organ that begins on the outside at the vaginal opening and extends about three to five inches inside, ending at the cervix, or neck of the uterus (womb).

Three Layers of Tissue
The vagina consists of three layers of tissue. The mucosa is the layer on the surface that can be touched. It consists of mucous membranes and is a surface similar to the lining of the mouth. Unlike the smooth surface of the mouth lining, the vagina contains folds or wrinkles. The next layer of tissue is a layer of muscle, concentrated mostly around the outer third of the vagina. The third, innermost layer consists of fibrous tissue that connects to other anatomical structures.

In the sexually unstimulated state, the vagina is shaped like a flattened tube, the sides of which are collapsed on each other. It is not a continually open space, or "hole" as often thought by both women and men. It is a potential space. Because of its muscular tissue, the vagina has the ability to expand and contract, like a balloon, allowing a baby to pass through during childbirth, or adjusting to fit snugly around a tampon, a finger or any size penis.

The internal walls of the vagina itself do not have a great supply of nerve endings, thus are not very sensitive to touch. The outer one-third of the vagina, especially near the opening, contains nearly 90 percent of the vaginal nerve endings and therefore is much more sensitive to touch than the inner two-thirds of the vaginal barrel.

Vaginal Fluid
During sexual excitement, droplets of fluid appear along the vaginal walls and eventually cover the sides of the vagina completely. The vaginal tissue does not contain any secretory glands itself, but is loaded with blood vessels, which when engorged with blood as a result of sexual arousal, press against the tissue, forcing natural tissue fluids through the walls of the vagina.

The fluid is not only a sign of sexual arousal, but serves as a lubricant for intercourse if that is what is to follow. Without this natural lubricant, or an artificial one, a woman would most likely find penetration painful. Sometimes the process of vaginal expansion and lubrication does not occur exactly as described or exactly when a woman would like. The causes of too little vaginal lubrication can be physical, emotional, or some combination of the two.

Physically, for example, it may be the result of a hormonal deficiency, or an infection or cyst in the vagina. Sometimes a woman who is using a birth control pill that is high in progesterone can experience lessened vaginal lubrication. 

Vaginal lubrication typically decreases as women age, but this is a natural physical change that does not normally mean there is any physical or psychological problem. After menopause, the body produces less estrogen, which, unless compensated for with estrogen replacement therapy, causes the vaginal walls to thin out significantly. The vagina also tends to become slightly shorter and narrower, and it takes longer to produce even a reduced amount of lubrication.

The vagina also loses its ability to expand as easily during sexual excitation. A woman not using estrogen replacement may use artificial lubricants, and engaging in longer periods of foreplay may help post-menopausal women avoid pain with intercourse. Sometimes after childbirth a woman's vagina may lose some of its muscle tone, loosen a bit, and feel larger. For some women this means that they may not feel the pleasure they once did from their partner's penis making contact with the vaginal walls. The partner may also notice that he is not held as tightly by the vagina.

Post-Childbirth Exercises
There are specific exercises that women can do after childbirth to strengthen and tighten the muscles around the vagina and improve the tone and feeling.These exercises, called Kegel exercises after the physician who developed them, require the woman to contract the muscles used to stop the flow of urine. The contraction is held for 3-5 seconds, repeated ten times in a series, and the series is usually repeated several times a day. These voluntary contractions can also be done during intercourse, and some women and men find it sexually enhancing.