Glans penis
Overview
The glans penis is the sensitive bulbous structure at the distal end of the penis
Penis
The penis is a biological feature of male animals including both vertebrates and invertebrates...

. The glans penis is anatomically homologous to the clitoral glans
Clitoral glans
The clitoral glans is an external portion of the clitoris.- Anatomy :It is covered by the clitoral hood, which is also external and attached to the labia minora...

 of the female. It is sometimes fully or partially covered by the foreskin
Foreskin
In male human anatomy, the foreskin is a generally retractable double-layered fold of skin and mucous membrane that covers the glans penis and protects the urinary meatus when the penis is not erect...

, except in men who have been fully circumcised
Circumcision
Male circumcision is the surgical removal of some or all of the foreskin from the penis. The word "circumcision" comes from Latin and ....

.

The glans is also commonly referred to as the "head of the penis", while common British slang
British slang
British slang is English language slang used in the UK. Slang is informal language sometimes peculiar to a particular social class or group and its use in Britain dates back to before the 16th century...

 terms include "helmet," "knob end" and "bell end", all referring to its distinctive shape.
Encyclopedia
The glans penis is the sensitive bulbous structure at the distal end of the penis
Penis
The penis is a biological feature of male animals including both vertebrates and invertebrates...

. The glans penis is anatomically homologous to the clitoral glans
Clitoral glans
The clitoral glans is an external portion of the clitoris.- Anatomy :It is covered by the clitoral hood, which is also external and attached to the labia minora...

 of the female. It is sometimes fully or partially covered by the foreskin
Foreskin
In male human anatomy, the foreskin is a generally retractable double-layered fold of skin and mucous membrane that covers the glans penis and protects the urinary meatus when the penis is not erect...

, except in men who have been fully circumcised
Circumcision
Male circumcision is the surgical removal of some or all of the foreskin from the penis. The word "circumcision" comes from Latin and ....

.

The glans is also commonly referred to as the "head of the penis", while common British slang
British slang
British slang is English language slang used in the UK. Slang is informal language sometimes peculiar to a particular social class or group and its use in Britain dates back to before the 16th century...

 terms include "helmet," "knob end" and "bell end", all referring to its distinctive shape. The medical name comes from Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 glans "acorn" + penis "of the penis" – the Latin genitive of this word has the same form as the nominative.

Medical considerations

The meatus
Urinary meatus
The urinary meatus is an orifice of the urethra. It is the point at which urine and, in males, semen exits the urethra. The meatus features varying degrees of sensitivity to the touch among males and females....

 (opening) of the urethra is at the tip of the glans penis. In circumcised
Circumcision
Male circumcision is the surgical removal of some or all of the foreskin from the penis. The word "circumcision" comes from Latin and ....

 infants, the foreskin no longer protects the meatal area of the glans; consequently, when wearing diaper
Diaper
A nappy or a diaper is a kind of pant that allows one to defecate or urinate on oneself discreetly. When diapers become soiled, they require changing; this process is often performed by a second person such as a parent or caregiver...

s, there may be greater risk of developing meatitis, meatal ulceration, and meatal stenosis
Meatal stenosis
Urethral meatal stenosis or urethral stricture is a narrowing of the opening of the urethra at the external meatus , thus constricting the opening through which urine leaves the body from the urinary bladder....

.

The epithelium of the glans penis is mucocutaneous tissue. Birley et al. report that excessive washing with soap may dry the mucous membrane that covers the glans penis and cause non-specific dermatitis
Dermatitis
-Etymology:Dermatitis derives from Greek derma "skin" + -itis "inflammation" and genetic disorder.-Terminology:There are several different types of dermatitis. The different kinds usually have in common an allergic reaction to specific allergens. The term may describe eczema, which is also called...

.

Inflammation of the glans penis is known as balanitis
Balanitis
Balanitis is inflammation of the glans penis . When the foreskin is also affected, it is termed balanoposthitis....

. It occurs in 3–11% of males, and up to 35% of diabetic males. It is more common among uncircumcised males. It has many causes, including irritation, or infection with a wide variety of pathogens. Careful identification of the cause with the aid of patient history, physical examination, swabs and cultures, and biopsy are essential in order to determine the proper treatment.

Anatomical details

The glans penis is the expanded cap of the corpus spongiosum
Corpus spongiosum
Corpus spongiosum is the mass of spongy tissue surrounding the male urethra within the penis...

. It is moulded on the rounded ends of the Corpora cavernosa penis
Corpus cavernosum penis
The corpus cavernosum penis is one of a pair of sponge-like regions of erectile tissue which contain most of the blood in the penis during penile erection...

, extending farther on their upper than on their lower surfaces. At the summit of the glans is the slit-like vertical external urethral orifice. The circumference of the base of the glans forms a rounded projecting border, the corona glandis, overhanging a deep retroglandular sulcus
Sulcus (anatomy)
A sulcus is a depression or fissure in the surface of an organ, especially the brain.-Elsewhere:* anterior interventricular sulcus* calcaneal sulcus* coronal sulcus* gingival sulcus* gluteal sulcus* interlabial sulci...

 (the coronal sulcus), behind which is the neck of the penis. The proportional size of the glans penis can vary greatly. On some penises it is much wider in circumference than the shaft, giving the penis a mushroom
Mushroom
A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus; hence the word "mushroom" is most often applied to those fungi that...

-like appearance, and on others it is narrower and more akin to a probe in shape. It has been suggested that the unique and unusual shape of the glans in humans has evolved to serve the function of "scooping" any remnant semen
Semen
Semen is an organic fluid, also known as seminal fluid, that may contain spermatozoa. It is secreted by the gonads and other sexual organs of male or hermaphroditic animals and can fertilize female ova...

 deposited by other rival males out of the deeper part of the vagina
Vagina
The vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...

 of a female who may have recently copulated, and thereby decreasing the chance of the rival male from impregnating the female. Other theorists suggest that its distinctive shape evolved to heighten the sexual pleasure experienced by the female during vaginal intercourse. In this theory, the glans increases friction and tension at the mouth of the vagina
Vagina
The vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...

 by its additional girth and the dilating properties of its probe-like shape.

The foreskin maintains the mucosa in a moist environment. In males who have been circumcised
Circumcision
Male circumcision is the surgical removal of some or all of the foreskin from the penis. The word "circumcision" comes from Latin and ....

, the glans is permanently exposed and dry. Szabo and Short found that the glans of the circumcised penis does not develop a thicker keratinization layer. Several studies have suggested that the glans is equally sensitive in circumcised and uncircumcised males, while others have reported that it is more sensitive in uncircumcised males (the interpretation of one of these studies is disputed).

Halata & Munger (1986) report that the density of genital corpuscles
Genital corpuscles
End-bulbs found in the penis and the clitoris have received the name of genital corpuscles; in these situations they have a mulberry-like appearance, being constricted by connective-tissue septa into from two to six knob-like masses.-External links:*...

 is greatest in the corona glandis, while Yang & Bradley (1998) report that their study "showed no areas in the glans to be more densely innervated than others."

Halata & Spathe (1997) reported that "the glans penis contains a predominance of free nerve endings, numerous genital end bulbs and rarely Pacinian
Pacinian corpuscle
Lamellar corpuscles or Pacinian corpuscles are one of the four major types of mechanoreceptor. They are nerve endings in the skin, responsible for sensitivity to vibration and pressure. Vibrational role may be used to detect surface, e.g., rough vs...

 and Ruffinian
Ruffini ending
The Bulbous corpuscle or Ruffini ending or Ruffini corpuscle is a class of slowly adapting mechanoreceptor thought to exist only in the glabrous dermis and subcutaneous tissue of humans...

 corpuscles. Merkel nerve ending
Merkel nerve ending
Merkel nerve endings are mechanoreceptors found in the skin and mucosa of vertebrates that provide touch information to the brain. The information they provide are those regarding pressure and texture. Each ending consists of a Merkel cell in close apposition with an enlarged nerve terminal...

s and Meissner's corpuscle
Meissner's corpuscle
Meissner's corpuscles are a type of mechanoreceptor. They are a type of nerve ending in the skin that is responsible for sensitivity to light touch. In particular, they have highest sensitivity when sensing vibrations lower than 50 Hertz...

s are not present."

Yang & Bradley argue that "The distinct pattern of innervation of the glans emphasizes the role of the glans as a sensory structure".

See also

  • Clitoris
    Clitoris
    The clitoris is a sexual organ that is present only in female mammals. In humans, the visible button-like portion is located near the anterior junction of the labia minora, above the opening of the urethra and vagina. Unlike the penis, which is homologous to the clitoris, the clitoris does not...

  • Corpus cavernosum penis
    Corpus cavernosum penis
    The corpus cavernosum penis is one of a pair of sponge-like regions of erectile tissue which contain most of the blood in the penis during penile erection...

  • Foreskin
    Foreskin
    In male human anatomy, the foreskin is a generally retractable double-layered fold of skin and mucous membrane that covers the glans penis and protects the urinary meatus when the penis is not erect...

  • Frenulum of prepuce of penis
    Frenulum of prepuce of penis
    The word frenulum on its own is often used for the frenulum of prepuce of penis, which is an elastic band of tissue under the glans penis that connects to the prepuce, or foreskin to the vernal mucosa, and helps contract the prepuce over the glans. This is sometimes colloquially known as the "banjo...

  • Hirsuties papillaris genitalis
    Hirsuties papillaris genitalis
    Hirsuties coronae glandis are small saliences on the ridge of the glans of the male genital organs. It is a harmless anatomical variation. They are found significantly more often on uncircumcised men, and on younger men...


External links

- "The Male Perineum and the Penis: The Corpus Spongiosum and Corpora Cavernosa" - "The Male Pelvis: The Urethra"
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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