Sunday, February 10, 2013

vulva


Vulva

From Wikipedia, the free encyclopedia
This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (May 2012)
Human vulva
Female unshaved genitalia.jpg
Human vulva with pubic hair
A vulva.jpeg
Vulva with hair trimmed
Latinpudendum femininum
Gray'ssubject #270 1264
ArteryInternal pudendal artery
VeinInternal pudendal veins
NervePudendal nerve
LymphSuperficial inguinal lymph nodes
PrecursorGenital tubercle, urogenital folds
MeSHVulva
Dorlands/ElsevierVulva
The vulva (from the Latin vulva, plural vulvae, see etymology) consists of the external genital organs of the female mammal.[1] This article deals with the vulva of the human being, although the structures are similar for other mammals.
The vulva has many major and minor anatomical structures, including the labia majora, mons pubis, labia minora, clitoris, bulb of vestibule, vulval vestibule, greater and lesser vestibular glands, and theopening of the vagina. Its development occurs during several phases, chiefly during the fetal and pubertal periods of time. As the outer portal of the human uterus or womb, it protects its opening by a "double door": the labia majora (large lips) and the labia minora (small lips). The vagina is a self-cleaning organ, sustaining healthy microbial flora that flow from the inside out; the vulva needs only simple washing to assure good vulvovaginal health, without recourse to any internal cleansing.
The vulva has a sexual function; these external organs are richly innervated and provide pleasure when properly stimulated. In various branches of art, the vulva has been depicted as the organ that has the power both to "give life" (often associated with the womb), and to give sexual pleasure to humankind.[2]
The vulva also contains the opening of the female urethra, but apart from this has little relevance to the function of urination.

Contents

  [hide] 

Structure

Vulva labeled
In human beings, major structures of the vulva are:[3]
Other structures:
Variation in the appearance of women's external genitalia
The soft mound at the front of the vulva is formed by fatty tissue covering the pubic bone, and is called the mons pubis. The term mons pubis is Latin for "pubic mound" and it is gender-nonspecific. There is, however, a variant term that specifies gender: in human females, the mons pubis is often referred to as the mons veneris, Latin for "mound of Venus" or "mound of love". The mons pubis separates into two folds of skin called the labia majora, literally "major (or large) lips". The cleft between the labia majorais called the pudendal cleft, or cleft of Venus, and it contains and protects the other, more delicate structures of the vulva. The labia majora meet again at a flat area between the pudendal cleft and the anus called the perineum. The color of the outside skin of thelabia majora is usually close to the overall skin color of the individual, although there is considerable variation. The inside skin and mucus membrane are often pink or brownish. After the onset of puberty, the mons pubis and the labia majora become covered by pubic hair. This hair sometimes extends to the inner thighs and perineum, but the density, texture, color, and extent of pubic hair coverage vary considerably, due to both individual variation and cultural practices of hair modification or removal.
The labia minora are two soft folds of skin within the labia majora. While labia minoratranslates as "minor (or small) lips", often the "minora" are of considerable size, and may protrude outside the "majora". Much of the variation among vulvas lies in the significant differences in the size, shape, and color of the labia minora.
The clitoris is located at the front of the vulva, where the labia minora meet. The visible portion of the clitoris is the clitoral glans. Typically, the clitoral glans is roughly the size and shape of a pea, although it can be significantly larger or smaller. The clitoral glans is highly sensitive, containing as many nerve endings as the analogous organ in males, the glans penis. The point where the labia minora attach to the clitoris is called the frenulum clitoridis. A prepuce, the clitoral hood, normally covers and protects the clitoris, however in women with particularly large clitorises or small prepuces, the clitoris may be partially or wholly exposed at all times. The clitoral hood is the female equivalent of the maleforeskin.[4] Often the clitoral hood is only partially hidden inside of the pudendal cleft.
The area between the labia minora is called the vulval vestibule, and it contains the vaginal and urethral openings. The urethral opening (meatus) is located below the clitoris and just in front of the vagina. This is where urine passes from the urinary bladder to be disposed of.
The opening of the vagina is located at the bottom of the vulval vestibule, toward the perineum. The term introitus is more technically correct than "opening", since the vagina is usually collapsed, with the opening closed, unless something is inserted. The introitus is sometimes partly covered by a membrane called the hymen. The hymen will rupture during the first episode of vigorous sex, and the blood produced by this rupture has been seen as a sign of virginity. However, the hymen may also rupture spontaneously during exercise (including horseback riding) or be stretched by normal activities such as use of tampons and menstrual cups, or be so minor as to be unnoticeable. In some rare cases, the hymen may completely cover the vaginal opening, requiring a surgical incision. Slightly below and to the left and right of the vaginal opening are two Bartholin glands which produce a waxy, pheromone-containing substance, the purpose of which is not yet fully known.
The appearance of the vulva and the size of the various parts varies a great deal from one female to another, and it is also common for the left and right sides to differ in appearance.

Fluids and odor

There are a number of different secretions associated with the vulva, including urine, sweat, menses, skin oils (sebum), Bartholin's and Skene's gland secretions, and vaginal wall secretions. These secretions contain a mix of chemicals, including pyridine, squalene, urea, acetic acid, lactic acid, complex alcohols, glycols, ketones, and aldehydes. During sexual arousal, vaginal lubrication increases.

Smegma

Smegma is a white substance formed from a combination of dead cells, skin oils, moisture and naturally occurring bacteria, that forms in mammalian genitalia. In females it collects around the clitoris and labial folds.

Aliphatic acids

Approximately one third of women produce aliphatic acids. These acids are a pungent class of chemicals which other primate species produce as sexual-olfactory signals. While there is some debate, researchers often refer to them as human pheromones. These acids are produced by natural bacteria resident on the skin. The acid content varies with the menstrual cycle, rising from one day after menstruation, and peaking mid-cycle, just before ovulation.

Sexual arousal

Main article: Human sexual response cycle
Sexual arousal results in a number of physical changes in the vulva. Arousal may be broken up into four somewhat arbitrary phases: Excitement, Plateau, Orgasm, and Resolution.
In the left image female genitalia are in the resting state. In the right image the female is sexually aroused, the vulva is moist and the labia are slightly swollen.

Excitement

Vaginal lubrication begins first. This is caused by vasocongestion of the vaginal walls. Increased blood pooling there causes moisture to seep from the walls. These droplets collect together and flow out of the vagina, moistening the vulva. The labia majoraflatten and spread apart, and the clitoris and labia minora increase in size.
Unlike an average man, whose sexual excitement will cause an obvious erection, a woman experiencing arousal may not be aware that her vagina has produced lubricationand has been engorged with blood.

Plateau

Increased vasocongestion in the vagina causes it to swell, decreasing the size of the vaginal opening by about 30%. The clitoris becomes increasingly erect, and the glans moves towards the pubic bone, becoming concealed by the hood. The labia minora increase considerably in thickness, approximately 2–6 times, causing them to spread apart, displaying the vaginal opening. The labia minora sometimes change considerably in color, going from pink to red in lighter skinned women who have not borne a child, or red to dark red in those that have.[citation needed]

Orgasm

Immediately prior to the female orgasm, the clitoris becomes exceptionally engorged, causing the glans to appear to retract into the clitoral hood. This is thought to protect the sensitive glans during orgasm. However, there is some doubt that this is the case, since the same engorgement prior to orgasm occurs in the male homologous structure, the penis, the function of which is thought to be to extend the penis as close to the cervix as possible prior to ejaculation.
Rhythmic muscle contractions occur in the outer third of the vagina, as well as the uterus and anus. They occur initially at a rate of about one every 0.8 seconds, becoming less intense and more randomly spaced as the orgasm continues. An orgasm may have as few as one or as many as 15 or more contractions, depending on its intensity. Orgasm may be accompanied by female ejaculation, causing liquid from either the Skene's gland or bladder to be expelled through the urethra.
Immediately after orgasm the clitoris may be so sensitive that any stimulation is either exciting or uncomfortable.

Resolution

The pooled blood begins to dissipate, although at a much slower rate if an orgasm has not occurred. The vagina and vaginal opening return to their normal relaxed state, and the rest of the vulva returns to its normal size, position and color.

Development

Fetus

Genital tubercle at fourteen weeks.
During the first eight weeks of life, both male and female fetuses have the same rudimentary reproductive and sexual organs, and maternal hormones control their development. Male and female organs begin to become distinct when the fetus is able to begin producing its own hormones, although visible determination of the sex is difficult until after the twelfth week.
During the sixth week, the genital tubercle develops in front of the cloacal membrane. The tubercle contains a groove termed the urethral groove. The urogenital sinus (forerunner of the bladder) opens into this groove. On either side of the groove are the urogenital folds. Beside the tubercle are a pair of ridges called the labioscrotal swellings.
Beginning in the third month of development, the genital tubercle becomes the clitoris. The urogenital folds become the labia minora, and the labioscrotal swellings become the labia majora.

Childhood

At birth, the neonate's vulva (and breast tissue—see witch's milk) may be swollen or enlarged as a result of having been exposed, via theplacenta, to her mother's increased levels of hormones. The clitoris is proportionally larger than it is likely to be later in life. Within a short period of time as these hormones wear off, the vulva will shrink in size.
From one year of age until the onset of puberty, the vulva does not undergo any change in appearance, other than growing in proportion with the rest of her body.

Puberty

The onset of puberty produces a number of changes. The structures of the vulva become proportionately larger and may become more pronounced. Coloration may change and pubic hair develops, first on the labia majora, and later spreading to the mons pubis, and sometimes the inner thighs and perineum.
In preadolescent girls, the vulva appears to be positioned further forward than in adults, showing a larger percentage of the labia majora and pudendal cleft when standing. During puberty the mons pubis enlarges, pushing the forward portion of the labia majora away from the pubic bone, and parallel to the ground (when standing). Variations in body fat levels affect the extent to which this occurs.

Childbirth

During childbirth, the vagina and vulva must stretch to accommodate the baby's head (approximately 9.5 cm or 3.7 in). This can result in tears in the vaginal opening, labia, and clitoris. An episiotomy (a preemptive surgical cutting of the perineum) is sometimes performed to limit tearing, but its appropriateness as a routine procedure is under question.
Some of the changes to the vagina and vulva that occur during pregnancy may become permanent.

Post-menopause

During menopause, hormone levels decrease, and as this process happens, reproductive tissues which are sensitive to these hormones shrink in size. The mons pubis, labia, and clitoris are reduced in size in post-menopause, although not usually to pre-puberty proportions.

Sexual homology

Main article: Sexual homology
Most male and female sex organs originate from the same tissues during fetal development; this includes the vulva. The anatomy of the vulva is related to the anatomy of the male genitalia by a shared developmental biology. Organs that have a common developmental ancestry in this way are said to be homologous.
The clitoral glans is homologous to the glans penis in males, and the clitoral body and the clitoral crura are homologous to the corpora cavernosa of the penis. The labia majora, labia minora, and clitoral hood are homologous to the scrotum, shaft skin of the penis, and theforeskin, respectively. The vestibular bulbs beneath the skin of the labia minora are homologous to the corpus spongiosum, the tissue of the penis surrounding the urethra. The Bartholin's glands are homologous to the Cowper's glands in males.

Society and culture

Many peoples have no or few taboos on exposure of the breasts, but the vulva and pubic triangle are always the first areas to be covered.Saartjie Baartman, the so-called "Hottentot Venus" who was exhibited in London at the beginning of the nineteenth century, was paid to display her large buttocks, but she never revealed her vulva. Khoisan women were said to have elongated labia, leading to questions about, and requests to exhibit, their sinus pudoris, "curtain of shame", or tablier (the French word for "apron"). To quote Stephen Jay Gould, "The labia minora, or inner lips, of the ordinary female genitalia are greatly enlarged in Khoi-San women, and may hang down three or four inches below the vagina when women stand, thus giving the impression of a separate and enveloping curtain of skin".[5] Baartman never allowed this trait to be exhibited while she was alive.[6]
Pubic hair removal is practiced in many cultures and has been common in the western world since the end of the 20th century.
Piercings of the vulva include the Christina piercing and theNefertiti piercing.
In some cultures, including modern Western culture, women have shaved or otherwisedepilated part or all of the vulva. When high-cut swimsuits became fashionable, women who wished to wear them would shave the sides of their pubic triangles, to avoid exhibiting pubic hair. Other women relish the beauty of seeing their vulva with hair, or completely hairless, and find one or the other more comfortable. Depilation of the vulva is a fairly recent phenomenon in the United States, Canada, and Western Europe, but has been prevalent, usually in the form of waxing, in many Eastern European and Middle Eastern cultures for centuries, usually due to the idea that it may be more hygienic, or originating in prostitution and pornography. Shaving may include all or nearly all of the hair. Some styles retain a small amount of hair on either side of the labia or a strip directly above and in line with the pudendal cleft. Many people object to pubic shaving, which can result in cuts to the vulva and clitoris, ingrown hairs, pseudofolliculitis barbae(razor bumps) and folliculitis.[7]
Since the early days of Islam, Muslim women and men have followed a tradition to "pluck the armpit hairs and shave the pubic hairs". This is a preferred practice rather than an obligation, and could be carried out by shaving, waxing, cutting, clipping, or any other method. This is a regular practice that is considered in some more devout Muslim cultures as a form of worship, not a shameful practice, while in other less devout regions it is a practice for the purpose of good hygiene. (See Islamic hygienical jurisprudence.) The reasons behind removing this hair could also be applied to the hair on the scrotum and around the anus, because the purpose is to be completely clean and pure and keep away from anything that may cause dirt and impurities.[8]
Several forms of genital piercings can be done in the female genital area. Piercings are usually performed for aesthetic purposes, but some forms like the Clitoral hood piercing might also enhance pleasure during sexual intercourse. Though they are common in traditional cultures, intimate piercings are a fairly recent trend in western culture.[9][10][11]

Altering the female genitalia

Main article: Genital modification and mutilation
The most prevalent form of genital alteration in some countries is female genital mutilation (FGM): removal of any part of the female genitalia for cultural, religious or other non-medical reasons. This practice is highly controversial as it is often done to non-consenting minors and for debatable (often misogynistic) reasons. An estimated 100 to 140 million girls and women in Africa and Asia have experienced some form of FGM.[12]
Labiaplasty: Reduction of the labia minora
Female genital surgery includes laser resurfacing of the labia to remove wrinkles,labiaplasty (reducing the size of the labia) and vaginal tightening. Some have likened labiaplasty to FGM.[13]
In September 2007, the American College of Obstetricians and Gynecologists issued a committee opinion on these and other female genital surgeries, including “vaginal rejuvenation,” “designer vaginoplasty”, “revirgination,” and “G-spot amplification.” This opinion states that the safety of these procedures has not been documented. ACOG recommends that women seeking these surgeries need to be informed about the lack of data supporting these procedures and the potential associated risks such as infection, altered sensation, dyspareunia, adhesions, and scarring.[14]

Etymology

The word vulva was taken from the Medieval Latin word volva or vulva ("womb, female genitals"), probably from the Old Latin volvere ("to roll"; lit. "wrapper"). This is similar toSanskrit word ulva ("womb").[15] An alternate term, also from Latin, is genitalia feminina externa[16] (female external genital organs).

Alternative terms

In slipshod colloquial speech, the term vagina is often wrongly used to refer to the female genitals generally. The vagina is a specific internalstructure, whereas the vulva is the whole exterior genitalia.
As with nearly any aspect of the human body involved in sexual or excretory functions, there are many slang words for the vulva.[17] "Cunt", a medieval word for the vulva and once the standard term, has become in its literal sense a vulgarism, and in other uses one of the strongest abusive obscenities in English-speaking cultures.

Depictions of vulvae

Main article: Depictions of nudity
Some cultures have tended to view the vulva as something shameful that should be hidden. For example, the term pudendum, which denotes the external genitalia, literally means "shameful thing".
Some cultures have long celebrated and even worshipped the vulva. Some Hindu sects revere it under the name yoni, and texts seem to indicate a similar attitude in some ancient Middle Eastern religions. As an aspect of Goddess worship such reverence may be part of modernNeopagan beliefs, and may be indicated in paleolithic artworks, dubbed "Old Europe" by archaeologist Marija Gimbutas. Ancient Greek women kept their vulva hairless so to display their beauty.

Slang

There are numerous slang words, euphemisms and synonyoms for the vulva in English and in other languages. See WikiSaurus:vulva for a list of slang words for vulva.

Art

Clinical relevance

See also: Vulvovaginal health

Injuries

The vulva is extremely sensitive to pleasure or pain due to its vast number of mechanoreceptors (nerve endings). Mechanoreceptors are pressure sensors in the human body, responsible for feeling any external changes. In the vulva, they number around 8000. Vulvular injuries are rare because its structure offers some natural protection, therefore it is protected from various forms of injuries.

Disorders

Gynaecology is the branch of medicine dealing with the diagnosis and treatment of the diseases and disorders associated with the female reproductive organs. Regular examinations are necessary to detect any abnormal changes in the vulvar region. Several pathologies are defined, a complete descriptive listing may be found in Chapter XIV of the list of ICD-10 codes; the most significant disorders include:

Blemishes and cysts

Infections

Inflammatory diseases

Pain syndromes

Vulvar cancer

Symptoms of vulvar cancer include itching, a lump or sore on the vulva which does not heal and/or grows larger, and sometimes discomfort/pain/swelling in the vulval area. Treatments include vulvectomy – removal of all or part of the vulva.

Ulcers

Developmental disorders

  • Septate vagina
  • Vaginal opening extremely close to the urethra or anus
  • An imperforate hymen
  • Various stages of genital masculinization including fused labia, an absent or partially formed vagina, urethra located on the clitoris.
  • Hermaphroditism

Other

Posted by at

No comments:

Post a Comment

Subscribe to: Post Comments (Atom)