Because of this and because a better understanding of female genitalia can help combat sexual and psychological harm with regard to female development, researchers endorse correct terminology for the vulva. Vaginal support structures Pelvic anatomy including organs of the female reproductive system The human vagina is an elastic, muscular canal that extends from the vulva to the cervix.
The part of the vagina surrounding the cervix is called the fornix. The urogenital triangle is the front triangle of the perineum and also consists of the urethral opening and associated parts of the external genitalia. Near the upper vagina, the cervix protrudes into the vagina on its front surface at approximately a 90 degree angle. The lateral walls, especially their middle area, are relatively more rigid. Because of this, the collapsed vagina has an H-shaped cross section.
The upper third are the levator ani muscles, and the transcervical, pubocervical , and sacrocervical ligaments. The opening to the vagina is normally obscured by the labia minora vaginal lips , but may be exposed after vaginal delivery. Where it is broken, it may completely disappear or remnants known as carunculae myrtiformes may persist. Otherwise, being very elastic, it may return to its normal position.
For these reasons, virginity cannot be definitively determined by examining the hymen. Human vaginal size The length of the vagina varies between women of child-bearing age. Because of the presence of the cervix in the front wall of the vagina, there is a difference in length between the front wall, approximately 7.
If a woman stands upright, the vaginal canal points in an upward-backward direction and forms an angle of approximately 45 degrees with the uterus. Development of the reproductive system An illustration showing a cut-away portion of the vagina and upper female genital tract only one ovary and fallopian tube shown. Circular folds also called rugae of vaginal mucosa can be seen The vaginal plate is the precursor to the vagina.
As the plate grows, it significantly separates the cervix and the urogenital sinus; eventually, the central cells of the plate break down to form the vaginal lumen. If the lumen does not form, or is incomplete, membranes known as vaginal septae can form across or around the tract, causing obstruction of the outflow tract later in life.
The two urogenital folds of the genital tubercle form the labia minora , and the labioscrotal swellings enlarge to form the labia majora.
Stratified squamous epithelium and underling connective tissue can be seen. The deeper muscular layers are not shown. The black line points to a fold in the mucosa. The vaginal wall from the lumen outwards consists firstly of a mucosa of stratified squamous epithelium that is not keratinized , with a lamina propria a thin layer of connective tissue underneath it. Secondly, there is a layer of smooth muscle with bundles of circular fibers internal to longitudinal fibers those that run lengthwise.
Lastly, is an outer layer of connective tissue called the adventitia. Some texts list four layers by counting the two sublayers of the mucosa epithelium and lamina propria separately. The muscular layer is composed of smooth muscle fibers, with an outer layer of longitudinal muscle, an inner layer of circular muscle, and oblique muscle fibers between.
The outer layer, the adventitia, is a thin dense layer of connective tissue and it blends with loose connective tissue containing blood vessels, lymphatic vessels and nerve fibers that are between pelvic organs.
It forms folds transverse ridges or rugae , which are more prominent in the outer third of the vagina; their function is to provide the vagina with increased surface area for extension and stretching. In these mid-layers of the epithelia, the cells begin to lose their mitochondria and other organelles. Between then to puberty , the epithelium remains thin with only a few layers of cuboidal cells without glycogen. The epidermis of the skin is relatively resistant to water because it contains high levels of lipids.
The vaginal epithelium contains lower levels of lipids. This allows the passage of water and water-soluble substances through the tissue. These form a network of smaller veins, the vaginal venous plexus , on the sides of the vagina, connecting with similar venous plexuses of the uterus , bladder , and rectum.
These ultimately drain into the internal iliac veins. The lower vagina is supplied by the pudendal nerve. Vaginal discharge and Vaginal lubrication Vaginal secretions are primarily from the uterus , cervix, and vaginal epithelium in addition to minuscule vaginal lubrication from the Bartholin's glands upon sexual arousal.
This initially forms as sweat-like droplets, and is caused by increased fluid pressure in the tissue of the vagina vasocongestion , resulting in the release of plasma as transudate from the capillaries through the vaginal epithelium. Human sexual activity and Human female sexuality Nerve endings in the vagina can provide pleasurable sensations when the vagina is stimulated during sexual activity. Women may derive pleasure from one part of the vagina, or from a feeling of closeness and fullness during vaginal penetration.
In addition to penile penetration, pleasure can come from masturbation , fingering , oral sex cunnilingus , or specific sex positions such as the missionary position or the spoons sex position. It is a sex organ of multiplanar structure containing an abundance of nerve endings, with a broad attachment to the pubic arch and extensive supporting tissue to the labia.
Research indicates that it forms a tissue cluster with the vagina. This tissue is perhaps more extensive in some women than in others, which may contribute to orgasms experienced vaginally. This begins after ten to thirty seconds of sexual arousal, and increases in amount the longer the woman is aroused.
The vagina lengthens during the arousal, and can continue to lengthen in response to pressure; as the woman becomes fully aroused, the vagina expands in length and width, while the cervix retracts. It is typically defined as being located at the anterior wall of the vagina, a couple or few inches in from the entrance, and some women experience intense pleasure, and sometimes an orgasm, if this area is stimulated during sexual activity.
When labor a physiological process preceding delivery nears, several signs may occur, including vaginal discharge, and the rupture of membranes water breaking that can result in a gush of amniotic fluid  or an irregular or small stream of fluid from the vagina. This allows the fetus to settle or "drop" into the pelvis. While these symptoms are likelier to happen after labor has begun for women who have given birth before, they may happen ten to fourteen days before labor in women experiencing labor for the first time.
The mucosa thickens and rugae return in approximately three weeks once the ovaries regain usual function and estrogen flow is restored. The vaginal opening gapes and is relaxed, until it returns to its approximate pre-pregnant state six to eight weeks after delivery, known as the postpartum period ; however, the vagina will continue to be larger in size than it was previously. List of microbiota species of the lower reproductive tract of women The vaginal flora is a complex ecosystem that changes throughout life, from birth to menopause.
The vaginal microbiota resides in and on the outermost layer of the vaginal epithelium. The vaginal microbiome is dominated by Lactobacillus species. Lactobacilli metabolize the sugar into glucose and lactic acid. The blades of the speculum are above and below and stretched vaginal walls are seen on the left and right. Vaginal health can be assessed during a pelvic examination , along with the health of most of the organs of the female reproductive system.
In the United States, Pap test screening is recommended starting around 21 years of age until the age of The vagina is assessed internally by the examiner with gloved fingers, before the speculum is inserted, to note the presence of any weakness, lumps or nodules. Inflammation and discharge are noted if present. During this time, the Skene's and Bartolin's glands are palpated to identify abnormalities in these structures.
After the digital examination of the vagina is complete, the speculum, an instrument to visualize internal structures, is carefully inserted to make the cervix visible. Sexual assault with objects can damage the vagina and X-ray examination may reveal the presence of foreign objects.
Pharmacologically , this has the potential advantage of promoting therapeutic effects primarily in the vagina or nearby structures such as the vaginal portion of cervix with limited systemic adverse effects compared to other routes of administration. Vaginal rings can also be used to deliver medication, including birth control in contraceptive vaginal rings.
These are inserted into the vagina and provide continuous, low dose and consistent drug levels in the vagina and throughout the body. Because the pudendal nerve carries motor and sensory fibers that innervate the pelvic muscles, a pudendal nerve block relieves birth pain. The medicine does not harm the child, and is without significant complications. Vaginal disease and Safe sex Vaginal infections or diseases include yeast infection , vaginitis , sexually transmitted infections STIs and cancer.
Lactobacillus gasseri and other Lactobacillus species in the vaginal flora provide some protection from infections by their secretion of bacteriocins and hydrogen peroxide. Both types can help avert pregnancy by preventing semen from coming in contact with the vagina. These nodes can be assessed for the presence of disease. Selective surgical removal rather than total and more invasive removal of vaginal lymph nodes reduces the risk of complications that can accompany more radical surgeries.
These selective nodes act as sentinel lymph nodes. It may be that their causes are the same. An applicator is inserted into the vagina to allow the administration of radiation as close to the site of the cancer as possible. The vaginal mucosa thickens and the vaginal pH becomes acidic again. Girls may also experience a thin, white vaginal discharge called leukorrhea. This causes atrophic vaginitis thinning and inflammation of the vaginal walls ,   which can lead to vaginal itching, burning, bleeding, soreness, or vaginal dryness a decrease in lubrication.
The vascular structures become fewer with advancing age. It is thought that the weakening of the support structures of the vagina is due to the physiological changes in this connective tissue.