(Source: Internet Archive Book Images)
The penis is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation, or sexual intercourse. It is the male genital organ of higher vertebrates that carries the duct for the transfer of sperm during sexual intercourse. In humans and most other mammals, it consists largely of erectile tissue and serves also for the elimination of urine. It lies between the legs of a man, above the testicles.
Most of the penis develops from the same tissue that becomes the clitoris in females during human development. The skin around the penis and the urethra come from the same tissue from which develops the labia minora in females.
There are three main parts to the penis:
Preceding and during sexual intercourse, the penis stiffens and rises in what is called an erection. The primary physical cause that brings about erection is the enlargement of the arteries that supply blood to the penis, which allows blood to fill the spongy tissue chambers in the penis, causing it to lengthen and stiffen.
Nuts & Bolts: What is the Penis?
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Copulation - sexual intercourse.
Erection - the stiffening and rising of the penis, which occurs during sexual arousal.
Inseminate - introduction of sperm into a female’s reproductive system for the purpose of impregnating or fertilizing the female for sexual reproduction.
Labia Minora - the smaller inner folds of the vulva.
Penis - the male genital organ of higher vertebrates, carrying the duct for the transfer of sperm during copulation. In humans and most other mammals, it consists largely of erectile tissue and serves also for the elimination of urine.
Perineum - the area between the anus and the scrotum or vulva.
For additional terminology related to male contraception and the male reproductive system, please visit our glossary:
Janet Leonard; Alex Cordoba-Aguilar R (18 June 2010). The Evolution of Primary Sexual Characters in Animals. Oxford University Press. ISBN 978-0-19-971703-3.
Marvalee H. Wake (15 September 1992). Hyman's Comparative Vertebrate Anatomy. University of Chicago Press. p. 583. ISBN 978-0-226-87013-7.
Julian Lombardi (1998). Comparative Vertebrate Reproduction. Springer. ISBN 978-0-7923-8336-9.
Tim Birkhead (2000). Promiscuity: An Evolutionary History of Sperm Competition. Harvard University Press. p. 102. ISBN 978-0-674-00666-9.
Virginia Douglass Hayssen; Ari Van Tienhoven (1993). Asdell's Patterns of Mammalian Reproduction: A Compendium of Species-Specific Data. Cornell University Press. ISBN 978-0-8014-1753-5.
Sue Taylor Parker; Karin Enstam Jaffe (2008). Darwin's Legacy: Scenarios in Human Evolution. AltaMira Press. p. 121. ISBN 978-0-7591-0316-0.
Geoffrey Miller (21 December 2011). The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature. Knopf Doubleday Publishing Group. ISBN 978-0-307-81374-9.
"Reproduction". University of Wisconsin. Archived from the original on 30 July 2012. Retrieved 3 October 2012.
Shackelford, T. K.; Goetz, A. T. (2007). "Adaptation to Sperm Competition in Humans". Current Directions in Psychological Science. 16: 47–50. doi:10.1111/j.1467-8721.2007.00473.x.
Alan F. Dixson (26 January 2012). Primate Sexuality: Comparative Studies of the Prosimians, Monkeys, Apes, and Humans. Oxford University Press. ISBN 978-0-19-150342-9.
Veale, D.; Miles, S.; Bramley, S.; Muir, G.; Hodsoll, J. (2015). "Am I normal? A systematic review and construction of nomograms for flaccid and erect penis length and circumference in up to 15 521 men". BJU International. 115 (6): 978–986. doi:10.1111/bju.13010.
Mammalogy. Jones & Bartlett Learning. 21 April 2011. pp. 389–. ISBN 978-0-7637-6299-5.
For additional publications related to male contraception and the male reproductive system, please visit our publications page: