Penis

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Corkscrew penis
)

Penis
Penis of an Asian elephant
Details
PrecursorGenital tubercle (amniotes)
SystemReproductive system, sometimes with the genitourinary system
Identifiers
Latinpenis
Anatomical terminology

In many

inseminate females (or hermaphrodites) during copulation.[1][2] Such organs occur in both vertebrates and invertebrates
, but males do not bear a penis in every animal species.

The term penis applies to many

Vertebrata, there are morphological variants with specific terminology, such as hemipenes
.

Etymology

The word "penis" is taken from the

tail". Some derive that from Indo-European *pesnis, and the Greek word πέος = "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 word yard used in this sense from 1379,[3] and notes that in his Physical Dictionary of 1684, Steven Blankaart defined the word penis as "the Yard, made up of two nervous Bodies, the Channel, Nut, Skin, and Fore-skin, etc."[4] According to Wiktionary
, this term meant (among other senses) "rod" or "bar".

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 φαλλος) is sometimes used to describe the penis, although "phallus" originally was used to describe representations, pictorial or carved, of the penis.[5]

Evolution and function

The external genital organs appeared in the Devonian, about 410 million years ago, when tetrapods began to abandon the aquatic environment.[6] In fact, it was necessary to overcome the absence of a liquid phase in which to release the gametes was achieved through the transition to internal fertilization.

Among amniotes, the development of an erectile penis occurred independently for

birds
).

Over time, birds have lost this organ, with the exception of

Paleognathae and Anseriformes.[7]

The penis is an

fertilization and, in the case of placentals, also for the excretion of urine.[8] The penises of different animal groups are not homologous
with each other, but were created several times independently of each other in the course of evolution.

An

spermatozoa
, from the penis.

The last common ancestor of all living amniotes (mammals, birds and reptiles) likely possessed a penis.[9]

Vertebrates

Birds

A mallard pseudo-penis[10]
Male ducks have a corkscrew-shaped penis while female ducks have corkscrew vaginas with many blind pockets designed for difficult penetration and to prevent becoming pregnant. This reduced the likelihood of fertilization by unwanted aggressors in favor of fitter mates.

Most male birds (e.g.,

ratites)[11] and Anatidae (ducks, geese and swans).[12] A bird penis is different in structure from mammal penises, being an erectile expansion of the cloacal wall (in ducks) and being erected by lymph, not blood.[13]
It is usually partially feathered and in some species features spines and brush-like filaments, and in a flaccid state, curls up inside the cloaca.

Mammals

As with any other bodily attribute, the length and girth of the penis can be highly variable between

distal part of the urethra in placental mammals. [8] The perineum of testicond mammals separates the anus
and the penis.

A bone called the baculum is present in most placental mammals but absent in humans, cattle and horses.

In mammals, the penis is divided into three parts:[16]

The internal structures of the penis consist mainly of cavernous,

blood sinusoids separated by sheets of connective tissue
(trabeculae).

Genitorinary system of a male raccoon (Procyon lotor)

Domestic cats have barbed penises, with about 120–150 one millimeter long backwards-pointing spines.[20] Monotremes and marsupial moles are the only mammals in which the penis is located inside the cloaca.[21][22]

Fish and reptiles

Male

evolutionary convergence, turtle and mammal penises have a similar structure.[24]

In some fish, the

are intromittent organs (to introduce sperm into the female) developed from modified fins.

Invertebrates

The spine-covered penis of Callosobruchus analis, a bean weevil

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 the cirrus.[25]

In 2010, entomologist Charles Linehard described Neotrogla, a new genus of barkflies. Species of this genus have sex-reversed genitalia. Females have penis-like organs called gynosomes that are inserted into vagina-like openings of males during mating.[26]

Heraldry

Pizzles are represented in heraldry, where the adjective pizzled (or vilené[27]) indicates that part of an animate charge's anatomy, especially if coloured differently.

See also

References

Citations

  1. from the original on 11 October 2013. Retrieved 20 July 2013.
  2. .
  3. .
  4. ]
  5. ^ "Online Etymology Dictionary". Etymonline.com. Archived from the original on 2011-06-06. Retrieved 2011-05-28.
  6. .
  7. .
  8. ^ from the original on 31 December 2013. Retrieved 23 July 2013.
  9. .
  10. .
  11. from the original on 26 March 2014. Retrieved 5 December 2012.
  12. on 26 March 2014. Retrieved 5 December 2012.
  13. from the original on 7 January 2014. Retrieved 5 December 2012.
  14. from the original on 26 March 2014. Retrieved 23 July 2013.
  15. . Retrieved 23 July 2013.
  16. from the original on 2018-03-20.
  17. from the original on 2014-03-26. Retrieved 2013-11-08.
  18. from the original on 26 March 2014. Retrieved 23 July 2013.
  19. (PDF) from the original on 2013-02-22.
  20. S2CID 13070242. Archived from the original
    (PDF) on 2017-06-20.
  21. ^ Gadow, H. On the systematic position of Notoryctes typhlops. Proc. Zool. Soc. London 1892, 361–370 (1892).
  22. ^ Riedelsheimer, B., Unterberger, P., Künzle, H. and U. Welsch. 2007. Histological study of the cloacal region and associated structures in the hedgehog tenrec Echinops telfairi. Mammalian Biology 72(6): 330-341.
  23. .
  24. ^ "Penis | Description, Anatomy, & Physiology | Britannica". Encyclopædia Britannica. January 2024.
  25. from the original on 2014-11-03.
  26. ^ Rietstap, J. B. (1884). "Armorial général; précédé d'un Dictionnaire des termes du blason". G. B. van Goor zonen: XXXI. Vilené: se dit un animal qui a la marque du sexe d'un autre émail que le corps {{cite journal}}: Cite journal requires |journal= (help)

General and cited references

Horses

Marsupials

Other animals

External links