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Penis
For other uses, see Penis (disambiguation).
This article is about penises of animals in general. For the human organ, see Human penis.
"Penile" redirects here. For the community in the United States, see Penile, Louisville.
"PENIS" redirects here. For the spectroscopy acronym, see Proton-enhanced nuclear induction spectroscopy.[img]//upload.wikimedia.org/wikipedia/commons/thumb/f/fc/Padlock-silver.svg/20px-Padlock-silver.svg.png[/img][img]//upload.wikimedia.org/wikipedia/commons/thumb/1/1f/Non-human_penises_Iceland_Phallological_Museum.jpg/220px-Non-human_penises_Iceland_Phallological_Museum.jpg[/img]Penises of minke whales on display at the Icelandic Phallological MuseumPenis(pluralpeniseslubconjunctionlublubor"],,0.709106207],["alboor"],,0.20001258],["czyoraniorbądźorczylior"],,0.00181349379],["względnieor"],,0.000519574678],["ewentualnieor"],,0.000300706743],["bobecausenounkolor złotykolor złotyor"],,6.51303651e-08],["złotogoldluborlubczyalboanibądźpenes) is a general term for the organs with which male and hermaphrodite animals introduce sperm into receptive females during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males do not bear a penis in every animal species, and in those species in which the male does bear a so-called penis, http://www.evi.com/q/http://www.hotelnovotel.rezerwuje.com the penes in the various species are not necessarily homologous. For example, the penis of a mammal is at most analogous to the penis of a male insect or barnacle.
The termpenisapplies to many reproductive intromittent organs, but not to all; for example the intromittent organ of most cephalopoda is the hectocotylus, a specialised arm, and male spiders use their pedipalps.
In most species of animals in which there is an organ that might reasonably be described as a penis, it has no major function other than intromission, or at least conveying the sperm to the female[potrzebne źródło], but in the placental mammals the penis bears the distal part of the urethra, which discharges both urine during urination and semen during copulation as the occasion requires.
In different animals
See also category: Animal penises
Vertebrates
See also: Intromittent organ#Vertebrata
Mammals
Further information: Sexual reproduction in male mammals
For the male human sexual organ, see Human penis.[img]//upload.wikimedia.org/wikipedia/commons/thumb/d/dc/Penis_asiatischer_Elefant.JPG/170px-Penis_asiatischer_Elefant.JPG[/img]Penis of an Asian elephant.
As with any other bodily attribute, the length and girth of the penis can be highly variable between individuals of the same species. In many animals, especially mammals, the size of a flaccid penis is smaller than its erect size.
A bone called the baculum oros penisis present in most mammals but absent in humans and horses.
In mammals the penis is divided into three parts:
- Roots (crura): these begin at the caudal border of the pelvic ischial arch.
- Body: the part of the penis extending from the roots.
- Glans: the free end of the penis.
The internal structures of the penis consist mainly of cavernous, erectile tissue, which is a collection of blood sinusoids separated by sheets of connective tissue (trabeculae). Some mammals have a lot of erectile tissue relative to connective tissue, for example horses. Because of this a horse's penis can enlarge more than a bull's penis. The urethra is on the ventral side of the body of the penis. As a general rule, a mammal's penis is proportional to its body size, but this varies greatly between species â even between closely related ones. For example, an adult gorilla's erect penis is about 4 cm (1.5 in) in length; an adult chimpanzee, significantly smaller (in body size) than a gorilla, has a penis size about double that of the gorilla. In comparison, the human penis is larger than that of any other primate, both in proportion to body size and in absolute terms.
Carnivorans
All members of Carnivora (except hyenas) have a baculum. In the Canoidea, the penis is highly specialized.
When a male spotted hyena copulates, his penis enters and exits the female's reproductive tract through her pseudo-penis instead of directly through the vagina, which is blocked by the false scrotum and testes. Once the female retracts her clitoris, the male enters the female by sliding beneath her, an operation facilitated by the penis' upward angle. The pseudo-penis closely resembles the male hyena's penis, but can be distinguished from the males' genitalia by its greater thickness and more rounded glans. In male spotted hyenas, as well as females, the base of the glans is covered with penile spines.
Domestic cats have barbed penises, with about 120â150 one millimeter long backwards-pointing spines. Upon withdrawal of the penis, the spines rake the walls of the female's vagina, which is a trigger for ovulation. Male lions also have barbed penises. Male felids usually urinate backwards by curving the tip of the glans penis backward. When male cheetahs urine-mark their territories, they stand one meter away from a tree or rock surface with the tail raised, pointing the penis either horizontally backward or 60° upward.
The male fossa has an unusually long penis and baculum (penis bone), reaching to between his forelegs when erect. The glans extends about halfway down the shaft and is spiny except at the tip. In comparison, the glans of felids is short and spiny, while that of viverrids is smooth and long.Fossa mating includes a copulatory tie, which may be enforced by the male's spiny penis. This unusually lengthy mating is due to the physical nature of the male's erect penis, which has backwards-pointing spines along most of its length. The male fossa has scent glands near the penis, with the penile glands emitting a strong odor.
The beech marten's penis is larger than the pine marten's, with the bacula of young beech martens often outsizing those of old pine martens.
Dogs
Main article: Canine penis
Male dogs, as well as wolves, have abulbus glandisat the base of their penises. The penis sometimes emerges from the fur-covered sheath during sexual arousal. During coitus thebulbus glandisswells up and results in a 'tie' (the male and female dogs being tied together). Muscles in the vagina of the female assist the retention by contracting.[potrzebne źródło] Male dogs have a conspicuous penis sheath. Male dogs also use their penises to direct urine when marking their territories.
At the time of penetration, the canine penis is not erect, and can only penetrate the female because it includes a narrow bone called the "baculum", a feature of most placental mammals. When the male achieves penetration, he will usually hold the female tighter and thrust deeply. It is during this time that the male's penis expands and it is important that the bulbus gland is sufficiently far enough inside for the female to be able to trap it. Unlike human sexual intercourse, where the male penis commonly becomes erect before entering the female, canine copulation involves the male first penetrating the female, after which swelling of the penis to erection occurs, which usually happens rapidly.
Male canines are the only animals that have a locking bulbus glandis or "bulb", a spherical area of erectile tissue at the base of the penis. During copulation, and only after the male's penis is fully inside the female's vagina, the bulbus glandis becomes engorged with blood. When the female's vagina subsequently contracts, the penis becomes locked inside the female. This is known as "tying" or "knotting". While characteristic of mating in most canids, the copulatory tie has been reported to be absent or very brief (less than one minute) in the African Wild Dog, possibly due to the abundance of large predators in its environment.
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Cetaceans
The penis on a right whale can be up to 2.7Â m (8.9Â ft) â the testes, at up to 2Â m (6.6Â ft) in length, 78Â cm (2.56Â ft) in diameter, and weighing up to 525Â lb (238Â kg), are also by far the largest of any animal on Earth.
The Blue Whale has the largest penis of any organism on the planet, typically measuring 8â10 feet. Accurate measurements of the blue whale are difficult to take because the whale's erect length can only be observed during mating.
Dolphins' reproductive organs are located on the underside of the body. Males have two slits, one concealing the penis and one further behind for the anus. On at least one occasion, a dolphin was known to tow bathers through the water by hooking his large penis around them. Between male bottlenose dolphins, homosexual behaviour includes rubbing of genitals against each other, which sometimes leads to the males swimming belly to belly, inserting the penis in the other's genital slit and sometimes anus.
Bats
Males of Racey's pipistrelle bat have a long, straight penis with a notch between the shaft and the narrow, egg-shaped glans penis. Near the top, the penis is haired, but the base is almost naked. In the baculum (penis bone), the shaft is long and narrow and slightly curved. The length of the penis and baculum distinguishP. raceyifrom all comparably sized African and Malagasy vespertilionids.P. endoi,P. paterculusiP. abramushave more similar bacula, but that ofP. abramusis more curved, the shaft and the tip are more robust inP. paterculus, and the proximal (near) end is more robust inP. endoi. In males, penis length is 9.6 to 11.8 mm (0.38 to 0.46 in) and baculum length is 8.8 to 10.0 mm (0.35 to 0.39 in).
Copulation by male greater short-nosed fruit bats is dorsoventral and the females lick the shaft or the base of the male's penis, but not the glans which has already penetrated the vagina. While the females do this, the penis is not withdrawn and research has shown a positive relationship between length of the time that the penis is licked and the duration of copulation. Post copulation genital grooming has also been observed.
Rodents
The glans penis of the marsh rice rat is long and robust, averaging 7.3 mm (0.29 in) long and 4.6 mm (0.18 in) broad, and the baculum (penis bone) is 6.6 mm (0.26 in) long. As is characteristic of Sigmodontinae, the marsh rice rat has a complex penis, with the distal (far) end of the baculum ending in three digits. The central digit is notably larger than those at the sides. The outer surface of the penis is mostly covered by small spines, but there is a broad band of nonspinous tissue The papilla (nipple-like projection) on the dorsal (upper) side of the penis is covered with small spines, a character the marsh rice rat shares only withOligoryzomysiconjunctioniiand"],,0.731615603],["aandzand"],,0.00122707128],["tajandadverbcoraz"],[["corazandiandiaorazOryzomys couesiamong oryzomyines examined. On the urethral process, located in the crater at the end of the penis, a fleshy process (the subapical lobule) is present; it is absent in all other oryzomyines with studied penes exceptO. couesiiconjunctioniiand"],,0.731615603],["aandzand"],,0.00122707128],["tajandadverbcoraz"],[["corazandiandiaorazHolochilus brasiliensis. The baculum is deeper than it is wide.
InTransandinomys talamancae, the outer surface of the penis is mostly covered by small spines, but there is a broad band of nonspinous tissue.
Some features of the accessory glands in the male genital region vary among oryzomyines. InTransandinomys talamancae, a single pair of preputial glands is present at the penis. As is usual for sigmodontines, there are two pairs of ventral prostate glands and a single pair of anterior and dorsal prostate glands. Part of the end of the vesicular gland is irregularly folded, not smooth as in most oryzomyines.
In Drymoreomys, there are three digits at the tip of the penis, of which the central one is the largest. The two lateral digits are not supported by mounds of the baculum (penis bone). There is only one spine on the papilla (nipple-like projection) on the upper side of the penis. On the urethral process, located in the crater at the end of the penis, a fleshy process at the side, the lateral lobule, is present. The preputial glands (glands in front of the genitals) are large. The lack of lateral bacular mounds, presence of a lateral lobule, and size of the preputial glands are all unique traits among the oryzomyines.
InThomasomys ucuchathe glans penis is rounded, short, and small and is superficially divided into left and right halves by a trough at the top and a ridge at the bottom. Most of the glans is covered with spines, except for an area near the tip.
The glans penis of a male cape ground squirrel is large with a prominent baculum.
Unlike the penises of other squirrel species, a red squirrel's penis is long, thin, and narrow, without a prominent baculum.
Winkelmann's mouse can easily be distinguished from its close relatives by the shape of its penis, which has a partially corrugated glans.
Primates
It has been postulated that the shape of the human penis may have been selected by sperm competition. The shape could have favored displacement of seminal fluids implanted within the female reproductive tract by rival males: the thrusting action which occurs during sexual intercourse can mechanically remove seminal fluid out of the cervix area from a previous mating.
The penis of the ring-tailed lemur is nearly cylindrical in shape and is covered in small spines, as well as having two pairs of larger spines on both sides. Males have a relatively small baculum (penis bone) compared to their size. The scrotum, penis, and prepuce are usually coated with a foul-smelling secretion.
The adult male of each vervet monkey species has a pale blue scrotum and a red penis, and male proboscis monkeys have a red penis with a black scrotum.
Male baboons and squirrel monkeys sometimes gesture with an erect penis as both a warning of impeding danger and a threat to predators. Genital display among male squirrel monkeys is an important social signal in relation to group hierarchy; it is derived from sexual behavior but is used for social communication. It involves the animal spreading his thighs and having an erect penis.
Humans
Main article: Human penis
The human penis is an external sexual organ of male humans. It is a reproductive, intromittent organ that additionally serves as the urinal duct. The main parts are the root of the penis (radix): It is the attached part, consisting of the bulb of penis in the middle and the crus of penis, one on either side of the bulb; the body of the penis (corpus); and the epithelium of the penis consists of the shaft skin, the foreskin, and the preputial mucosa on the inside of the foreskin and covering the glans penis.
The human penis is made up of three columns of tissue: two corpora cavernosa lie next to each other on the dorsal side and one corpus spongiosum lies between them on the ventral side. The urethra, which is the last part of the urinary tract, traverses the corpus spongiosum, and its opening, known as the meatus /miËËeÉŞtÉs/, lies on the tip of the glans penis. It is a passage both for urine and for the ejaculation of semen.
In males, the expulsion of urine from the body is done through the male penis. The urethra drains the bladder through the prostate gland where it is joined by the ejaculatory duct, and then onward to the penis.
An erection is the stiffening and rising of the penis, which occurs during sexual arousal, though it can also happen in non-sexual situations. Ejaculation is the ejecting of semen from the penis, and is usually accompanied by orgasm. A series of muscular contractions delivers semen, containing male gametes known as sperm cells or spermatozoa, from the penis.
The most common form of genital alteration is circumcision: removal of part or all of the foreskin for various cultural, religious, and more rarely medical reasons. There is controversy surrounding circumcision.
While results vary across studies, the consensus is that the average erect human penis is approximately 12.9â15Â cm (5.1â5.9Â in) in length with 95% of adult males falling within the interval 10.7â19.1Â cm (4.2â7.5Â in). Neither patient age nor size of the flaccid penis accurately predicted erectile length.
Horses
See also: Horse sheath cleaning and Stallion#Reproductive anatomy
Stallions have a vascular penis. When non-erect, it is quite flaccid and contained within the prepuce (foreskin, or sheath). The retractor penis muscle is relatively underdeveloped. Erection and protrusion take place gradually, by the increasing tumescence of the erectile vascular tissue in thecorpus cavernosum penis. When not erect, the penis is housed within the prepuce, 50 centimetres (20Â in) long and 2.5 to 6 centimetres (0.98 to 2.4 in) in diameter with the distal end 15 to 20 centimetres (5.9 to 7.9 in). The retractor muscle contracts to retract the penis into the sheath and relaxes to allow the penis to extend from the sheath. When erect, the penis doubles in length and thickness and the glans increases by 3 to 4 times. The urethra opens within theurethral fossa, a small pouch at the distal end of the glans.
A structure called the urethral process projects beyond the glans.
Other mammals
The penis of a pronghorn antelope is about 5 inches long, and is shaped like an ice pick. When mating, the tip of the male pronghorn's penis is often the first part to touch the female pronghorn. The front of a pronghorn's glans penis is relatively flat, while the back is relatively thick.
An adult elephant has the largest penis of any land animal at 6 feet (1.8Â m) on average. An elephant's penis can reach a length of 100Â cm (39Â in) and a diameter of 16Â cm (6Â in) at the base. It is S-shaped when fully erect and has a Y-shaped orifice. During musth, a male elephant may urinate with his penis still in the sheath, which causes the urine to spray on the hind legs. An elephant's penis is very mobile, being able to move independently of the male's pelvis, and the penis curves forward and upward prior to mounting another elephant.
In giant anteaters, the (retracted) penis and testes are located internally between the rectum and urinary bladder.
The penis of a dromedary camel is covered by a triangular penile sheath opening backwards, and is about 60Â cm (24Â in) long. The camelmen often aid the male to enter his penis into the female's vulva, though the male is considered able to do it on his own. Copulation time ranges from 7â35 minutes, averaging 11â15 minutes.
WhenC. villosusis sexually aroused with an erect penis, species determination is easier. Its penis can be as long as 35Â mm, and usually remains completely withdrawn inside a skin receptacle. Scientists conducting studies on theC. villosuspenis muscles revealed this species' very long penis exhibits variability. During its waking hours, it remains hidden beneath a skin receptacle, until it becomes erect and it projects outside in a rostral direction. During its slow wave sleep phase, penile protrusion makes some very complex movements. The penis during this phase is not erect, but remains outside of its receptacle. During paradoxical sleep, no erections occur, and the penile muscles share the characteristics of the rest of the body.
Tapirs have exceptionally long penises relative to their body size.
A stag's penis forms an S-shaped curve when it is not erect, and is retracted into its sheath by the retractor penis muscle. Some deer species spray urine on their bodies by urinating from an erect penis. One type of scent-marking behavior in elk is known as "thrash-urination, which typically involves palpitation of the erect penis. A male elk's urethra points upward so that urine is sprayed almost at a right angle to the penis. A sambar stag will mark himself by spraying urine directly in the face with a highly mobile penis, which is often erect during its rutting activities.Red deer stags often have erect penises during combat.
Bulls have a fibro-elastic penis. Given the small amount of erectile tissue, there is little enlargement after erection. The penis is quite rigid when non-erect, and becomes even more rigid during erection. Protrusion is not affected much by erection, but more by relaxation of the retractor penis muscle and straightening of the sigmoid flexure. Bulls are occasionally affected by a condition known as "corkscrew penis". The penis of a mature bull is about 3â4Â cm in diameter.
Most marsupials, except for the two largest species of kangaroos[clarify], have a bifurcated penis, separated into two columns, so that the penis has two ends corresponding to the females' two vaginas. Neither marsupials nor monotremes possess a baculum. When not erect, it is retracted into the body in an S-shaped curve. The shape of the glans varies among species. A male koala's foreskin contains naturally occurring bacteria that play an important role in fertilization. The penises of marsupials curve forward when erect.
Bulls, rams and boars have an S-shaped penis with a sigmoid flexure which straightens out during erection.[potrzebne źródło] A boar's penis is about 18 inches long, and ejaculates about a pint of semen.
In the realm of absolute size, the smallest vertebrate penis belongs to the common shrew (5Â mm or 0.2Â inches).[potrzebne źródło]
Male echidnas have a four-headed penis. During mating, the heads on one side "shut down" and do not grow in size; the other two are used to release semen into the female's two-branched reproductive tract. The heads used are swapped each time the mammal copulates. When not in use, the penis is retracted inside a preputial sac in the cloaca. The male echidna's penis is 7 centimeters long when erect, and its shaft is covered with penile spines. The male short-beaked echidna has a highly unusual penis with four knobs on the tip, which is nearly a quarter of his body length when erect. Each side of the bilaterally symmetrical, rosette-like, four-headed penis [similar to that of reptiles and 7 centimetres (2.8Â in) in length] is used alternately, with the other half being shut down between ejaculations.
Other vertebrates[img]//upload.wikimedia.org/wikipedia/commons/7/75/Mallard_with_visible_pseudo-penis_%28croped%29.jpg[/img]Mallard pseudo-penis
Most male birds (e.g., roosters and turkeys) have a cloaca (also present on the female), but not a penis. Among bird species with a penis are paleognathes (tinamous and ratites),Anatidae (ducks, geese and swans), and a very few other species (including flamingoes[potrzebne źródło] and chickens). A bird penis is different in structure from mammal penises, being an erectile expansion of the cloacal wall and being erected by lymph, not blood. It is usually partially feathered and in some species features spines and brush-like filaments, and in flaccid state curls up inside the cloaca. The Argentine Blue-bill has the largest penis in relation to body size of all vertebrates; while usually about half the body size (20Â cm), a specimen with a penis 42.5Â cm long is documented.
The Lake Duck is notable for possessing, in relation to body length, the longest penis of all vertebrates; the penis, which is typically coiled up in flaccid state, can reach about the same length as the animal himself when fully erect, but more commonly is about half the bird's length. It is theorized that the remarkable size of their spiny penises with bristled tips may have evolved in response to competitive pressure in these highly promiscuous birds, removing sperm from previous matings in the manner of a bottle brush.
Although most male birds have no penis, ducks have a long corkscrew penis, and the females have a long corkscrew vagina, which spirals in the opposite direction. The males often try to force copulation, but the complex mating geometry allows the females to retain controlâmost forced copulations do not result in successful fertilisation.
Male and female emus are similar in appearance, although the male's penis can become visible when it defecates.
The male tinamou has a corkscrew shaped penis, similar to those of the ratites and to the hemipenis of some reptiles. Females have a small phallic organ in the cloaca which becomes larger during the breeding season.
Male turtles and crocodiles have a penis, while male specimens of the reptile order Squamata have two paired organs called hemipenes. Tuataras must use their cloacae for reproduction.
In some fishes, the gonopodium, andropodium, and claspers are intromittent organs (to introduce sperm into the female) developed from modified fins.
Invertebrates
Main article: Intromittent organ#Invertebrates[img]//upload.wikimedia.org/wikipedia/commons/thumb/f/f7/Callosobruchus_analis_penis.jpg/220px-Callosobruchus_analis_penis.jpg[/img]The spine-covered penis ofCallosobruchus analis, a Bean weevil.
The record for the largest penis to body size ratio is held by the barnacle. The barnacle's penis can grow to up to forty times its own body length. This enables them to reach the nearest female.
A number of invertebrate species have independently evolved the mating technique of traumatic insemination where the penis penetrates the female's abdomen and deposits sperm in the wound it produces. This has been most fully studied in bed bugs.
The penis in most male Coleoidea is a long and muscular end of the gonoduct used to transfer spermatophores to a modified arm called a hectocotylus. That, in turn, is used to transfer the spermatophores to the female. In species where the hectocotylus is missing, the penis is long and able to extend beyond the mantle cavity and transfers the spermatophores directly to the female. Deep water squid have the greatest known penis length relative to body size of all mobile animals, second in the entire animal kingdom only to certain sessile barnacles Penis elongation inOnykia ingensmay result in a penis that is as long as the mantle, head and arms combined.Giant squid of the genusArchiteuthisare unusual in that they possess both a large penis and modified arm tips, although it is uncertain whether the latter are used for spermatophore transfer.
Insects
In male insects, the structure analogous to a penis is known as aedeagus. The male copulatory organ of various lower invertebrate animals is often called thecirrus.[potrzebne źródło]
The lesser water boatman's mating call, generated by rubbing the penis against the abdomen, is the loudest sound, relative to body size, in the animal kingdom.
Etymology
The word "penis" is taken from the Latin word for "tail." Some derive that from Indo-European*pesnis, and the Greek word ĎÎÎżĎ = "penis" from Indo-European*pesos. Prior to the adoption of the Latin word in English the penis was referred to as a "yard". The Oxford English Dictionary cites an example of the wordyardused in this sense from 1379, and notes that in hisPhysical Dictionaryof 1684, Steven Blankaart defined the wordpenisas "the Yard, made up of two nervous Bodies, the Channel, Nut, Skin, and Fore-skin, etc."
As with nearly any aspect of the body involved in sexual or excretory functions, the penis is the subject of many slang words and euphemisms for it, a particularly common and enduring one being "cock". See WikiSaurus:penis for a list of alternative words for penis.
The Latin word"phallus"(from Greek ĎιΝΝοĎ) is sometimes used to describe the penis, although "phallus" originally was used to describerepresentations, pictorial or carved, of the penis.
Pizzle, an archaic English word for penis, of Low German or Dutch origin, is now used to denote the penis of a non-human animal.[potrzebne źródło]
The adjectival form of the word penis is penile. This adjective is commonly used in describing various accessory structures of male copulatory organs found in many kinds of invertebrate animals.[potrzebne źródło]
Human use of animal penises
Pizzles are represented in heraldry, where the adjectivepizzled(lubvilenĂŠ) indicates that part of an animate charge's anatomy, especially if coloured differently.
See also
- Buried penis
- Castration anxiety
- Diphallia
- Dildo
- Erogenous zone
- Koteka
- Micropenis
- Penis enlargement
- Penis envy
- Penis removal
- Phallic architecture
- Preputioplasty
- Pubic hair
- Stamen
- Stunt cock
- Testicle
Notes
Bibliography
- Brehm, Alfred Edmund (1895).Brehm's Life of Animals. Chicago: A. N. Marquis & CompanyÂ
- Heptner, V. G.; Sludskii, A. A. (2002).Mammals of the Soviet Union. Vol. II, part 1b, Carnivores (Mustelidae and Procyonidae). Washington, D.C. : Smithsonian Institution Libraries and National Science Foundation. ISBN 90-04-08876-8Â
External links
-[img]//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/12px-Commons-logo.svg.png[/img]Media related to Penis at Wikimedia Commons
- Kinsey Institute on the penis
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