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Urination is the release of urine from the bladder through the urethra in Placentalia, or through the cloaca in other . It is the urinary system's form of excretion. It is also known medically as micturition, voiding, uresis, or, rarely, emiction, and known colloquially by various names including peeing, weeing, pissing, and euphemistically number one. The process of urination is under voluntary control in healthy humans and other animals, but may occur as a reflex in infants, some elderly individuals, and those with neurological injury. It is normal for adult humans to urinate up to seven times during the day.
In some animals, in addition to expelling waste material, urination can mark territory or express submissiveness. Physiologically, urination involves coordination between the central, autonomic, and somatic nervous systems. Brain centres that regulate urination include the pontine micturition center, periaqueductal gray, and the cerebral cortex.
Smooth muscle bundles pass on either side of the urethra, and these fibers are sometimes called the internal urethral sphincter, although they do not encircle the urethra. Further along the urethra is a sphincter of skeletal muscle, the sphincter of the membranous urethra (external urethral sphincter). The bladder's epithelium is termed transitional epithelium which contains a superficial layer of dome-like cells and multiple layers of stratified cuboidal cells underneath when evacuated. When the bladder is fully distended the superficial cells become squamous (flat) and the stratification of the cuboidal cells is reduced in order to provide lateral stretching.
In healthy individuals, the lower urinary tract has two discrete phases of activity: the storage (or guarding) phase, when urine is stored in the bladder; and the voiding phase, when urine is released through the urethra. The state of the reflex system is dependent on both a conscious signal from the brain and the firing rate of sensory fibers from the bladder and urethra. At low bladder volumes, afferent firing is low, resulting in excitation of the outlet (the sphincter and urethra), and relaxation of the bladder. At high bladder volumes, afferent firing increases, causing a conscious sensation of urinary urge. Individual ready to urinate consciously initiates voiding, causing the bladder to contract and the outlet to relax. Voiding continues until the bladder empties completely, at which point the bladder relaxes and the outlet contracts to re-initiate storage. The muscles controlling micturition are controlled by the autonomic and somatic nervous systems. During the storage phase, the internal urethral sphincter remains tense and the detrusor muscle relaxed by sympathetic stimulation. During micturition, parasympathetic stimulation causes the detrusor muscle to contract and the internal urethral sphincter to relax. The external urethral sphincter (sphincter urethrae) is under somatic control and is consciously relaxed during micturition.
In infants, voiding occurs involuntarily (as a reflex). The ability to voluntarily inhibit micturition develops by the age of two–three years, as control at higher levels of the central nervous system develops. In the adult, the volume of urine in the bladder that normally initiates a reflex contraction is about .
Action potentials carried by sensory neurons from stretch receptors in the urinary bladder wall travel to the sacral segments of the spinal cord through the pelvic nerves. Since bladder wall stretch is low during the storage phase, these afferent neurons fire at low frequencies. Low-frequency afferent signals cause relaxation of the bladder by inhibiting sacral parasympathetic preganglionic neurons and exciting lumbar sympathetic preganglionic neurons. Conversely, afferent input causes contraction of the sphincter through excitation of Onuf's nucleus, and contraction of the bladder neck and urethra through excitation of the sympathetic preganglionic neurons.
Diuresis (production of urine by the kidney) occurs constantly, and as the bladder becomes full, afferent firing increases, yet the micturition reflex can be voluntarily inhibited until it is appropriate to begin voiding.
Bladder afferent signals ascend the spinal cord to the periaqueductal gray, where they project both to the pontine micturition center and to the cerebrum. At a certain level of afferent activity, the conscious urge to void or urination urgency, becomes difficult to ignore. Once the voluntary signal to begin voiding has been issued, neurons in the pontine micturition center fire maximally, causing excitation of sacral preganglionic neurons. The firing of these neurons causes the wall of the bladder to contract; as a result, a sudden, sharp rise in intravesical pressure occurs. The pontine micturition center also causes inhibition of Onuf's nucleus, resulting in relaxation of the external urinary sphincter. When the external urinary sphincter is relaxed urine is released from the urinary bladder when the pressure there is great enough to force urine to flow out of the urethra. The micturition reflex normally produces a series of contractions of the urinary bladder.
The flow of urine through the urethra has an overall excitatory role in micturition, which helps sustain voiding until the bladder is empty.
Many men, and some women, may sometimes Pee shivers after or during urination.
After urination, the female urethra empties partially by gravity, with assistance from muscles. Urine remaining in the male urethra is expelled by several contractions of the bulbospongiosus muscle, and, by some men, manual squeezing along the length of the penis to expel the rest of the urine.
For land mammals over 1 kilogram, the duration of urination does not vary with body mass, being dispersed around an average of 21 seconds (standard deviation 13 seconds), despite a 4 order of magnitude (1000×) difference in bladder volume. This is due to increased urethra length of large animals, which amplifies gravitational force (hence flow rate), and increased urethra width, which increases flow rate. For smaller mammals a different phenomenon occurs, where urine is discharged as droplets, and urination in smaller mammals, such as mice and rats, can occur in less than a second. The posited benefits of faster voiding are decreased risk of predation (while voiding) and decreased risk of urinary tract infection.
There is an inhibitory area for micturition in the midbrain. After transection of the brain stem just above the pons, the threshold is lowered and less bladder filling is required to trigger it, whereas after transection at the top of the midbrain, the threshold for the reflex is essentially normal. There is another facilitatory area in the posterior hypothalamus. In humans with lesions in the superior frontal gyrus, the desire to urinate is reduced and there is also difficulty in stopping micturition once it has commenced. However, stimulation experiments in animals indicate that other cortical areas also affect the process.
The bladder can be made to contract by voluntary facilitation of the spinal voiding reflex when it contains only a few milliliters of urine. Voluntary contraction of the abdominal muscles aids the expulsion of urine by increasing the pressure applied to the urinary bladder wall, but voiding can be initiated without straining even when the bladder is nearly empty. Voiding can also be consciously interrupted once it has begun, through a contraction of the perineal muscles. The external sphincter can be contracted voluntarily, which will prevent urine from passing down the urethra.
An alternative solution (for traveling, , etc.) is a special disposable bag containing absorbent material that solidifies the urine within seconds, making it convenient and safe to store and dispose of later.
It is possible for both sexes to urinate into bottles in case of emergencies. The technique can help children to urinate discreetly inside cars and in other places without being seen by others. A female urination device can assist women and girls in urinating while standing or into a bottle.
In microgravity, excrement tends to float freely, so astronauts use a specially designed space toilet, which uses suction to collect and recycle urine; the space toilet also has a receptacle for defecation.
Chemical toilet (port-a-potties) are frequently placed in outdoor situations where no immediate facility is available. These need to be serviced (cleaned out) on a regular basis. Urination in a heavily wooded area is generally harmless, actually saves water, and may be condoned for males (and less commonly, females) in certain situations as long as common sense is used. Examples (depending on circumstances) include activities such as camping, hiking, delivery driving, cross country running, rural fishing, amateur baseball, golf, etc.
The more developed and crowded a place is, the more public urination tends to be objectionable. In the countryside, it is more acceptable than in a street in a town, where it may be a common transgression. Often this is done after the consumption of alcoholic beverages, which causes production of additional urine as well as a reduction of inhibitions. One proposed way to inhibit public urination due to drunkenness is the Urilift, which is disguised as a normal manhole by day but raises out of the ground at night to provide a public restroom for bar-goers.
In many places, public urination is punishable by fines, though attitudes vary widely by country. In general, females are less likely to urinate in public than males. Women and girls, unlike men and boys, are restricted in where they can urinate conveniently and discreetly.The new ourselves, growing older: women aging with knowledge and power, Paula Brown Doress-Worters, Diana Laskin Siegal, Boston Women's Health Book Collective, Simon & Schuster, 1994, Page 301
The 5th-century BC historian Herodotus, writing on the culture of the ancient Persians and highlighting the differences with those of the Ancient Greece, noted that to urinate in the presence of others was prohibited among Persians.
There was a popular belief in the UK, that it was legal for a man to urinate in public so long as it occurred on the rear wheel of his vehicle and he had his right hand on the vehicle, but this is not true. Public urination still remains more accepted by males in the UK, although British cultural tradition itself seems to find such practices objectionable.
In Islamic toilet etiquette, it is haram to urinate while facing the Qibla, or to turn one's back to it when urinating or relieving bowels, but modesty requirements for females make it impossible for girls to relieve themselves without facilities.Unveiling the Breath: One Woman's Journey Into Understanding Islam and Gender Equality, Donna Kennedy-Glans pg. 69 (1986). 9789976956054, Bilal Muslim Mission of Tanzania. ISBN 9789976956054 When toilets are unavailable, females can relieve themselves in Laos, Russia and Mongolia in emergency, but it remains less accepted for females in India even when circumstances make this a highly desirable option. (2025). 9780231502962, Columbia University Press. ISBN 9780231502962
Women generally need to urinate more frequently than men, but as opposed to the common misconception, it is not due to having smaller bladders. Resisting the urge to urinate because of lack of facilities can promote urinary tract infections which can lead to more serious infections and, in rare situations, can cause Renal failure in women. Female urination devices are available to help women to urinate discreetly, as well to help them urinate while standing.
Some squat as it is the natural posture in which the body aligns the bladder properly and gravity helps to completely empty the bladder which prevents various complications like UTI, which is gender neutral.
Elderly males with prostate gland enlargement may benefit from sitting down to urinate, with the seated voiding position found superior as compared with standing in elderly males with benign prostate hyperplasia.
In Germany, the practice of men urinating while sitting was promoted in the 1990s, primarily for hygienic reasons.Albert Hauser: Das Sitzpinkel-Manifest. Hier sitzt Mann. Eichborn Verlag, Frankfurt am Main, 1997, ISBN 9783821830506.Bettina Möllring: Toiletten und Urinale für Frauen und Männer – die Gestaltung von Sanitärobjekten und ihre Verwendung in öffentlichen und privaten Bereichen. Dissertation, Universität der Künste Berlin, 2003, S. 22Lisa Ortgies, Svea Große: Pinkeln im Stau und andere Katastrophen. Der Survivalguide für Frauen. vgs Verlagsgesellschaft, 2003, ISBN 3-8025-1505-6 While urine is sterile, the residue could potentially be colonized by E. coli.Tadd Truscott; Randy Hurt: Urinal Dynamics: A Tactical Summary. 2013 In 2014, urologists at the Leiden University Medical Center in the Netherlands published a study stating that sitting is the better position for urination, even for men with prostate enlargement problems.de Jong Y, Pinckaers JHFM, ten Brinck RM, Lycklama a` Nijeholt AAB, Dekkers OM: Urinating Standing versus Sitting: Position Is of Influence in Men with Prostate Enlargement. A Systematic Review and Meta-Analysis. PLoS ONE 9(7) Urologist Wolfgang Bührmann noted in 2017 that younger generations were increasingly willing to sit down, attributing this to changing gender roles, with men doing more cleaning of the bathroom. Männer, wir haben bei der Sitzpinkel-Debatte ein wichtiges Detail übersehen. Die Zeit, 15. August 2017 According to a 2023 study by the British market research company YouGov, Germany has the highest proportion of men (over 55 years old) who sit down to urinate. In this study, 40% of German men reported always sitting down, with Sweden following in second place with 22%. Deutsche Männer sind Sitzpinkler. Yougov.de, 22. Mai 2023 Deutsche sind die größten Sitzpinkler. Frankfurter Allgemeine, 17. Mai 2023 A survey in Japan from 2020 found that 70% of Japanese men urinate sitting down, up from 51% five years earlier. The Splashback Scandal: Should All Men Sit Down to Urinate? The Guardian, 20. Februar 2023 Give Pee a Chance: Why German Men Urinate Sitting Down. bigthink.com, 24. März 2023 Among married men, the proportion was higher than among unmarried men.Noritoshi Sekido et al.: Is Seated Voiding Associated with Lower Urinary Tract Symptoms, Health Conditions, or Marital Status? Findings by Age Group from the 2023 Japan Community Health Survey. International Journal of Urology, 25. Oktober 2024,
Females may also urinate while standing, and while clothed. It is common for women in various regions of Africa to use this position when they urinate, as do women in Laos. Herodotus described a similar custom in ancient Egypt. An alternative method for women voiding while standing is to use a female urination device to assist., ABC 2 News, Maryland, 3 September 2009
Many expressions exist, some euphemism and some vulgar. For example, centuries ago the standard English word (both noun and verb, for the product and the activity) was "", but subsequently "pee", formerly associated with children, has become more common in general public speech. Since elimination of bodily wastes is, of necessity, a subject talked about with toddlers during toilet training, other expressions considered suitable for use by and with children exist, and some continue to be used by adults, e.g. "weeing", "doing/having a wee-wee", "to tinkle", "", "go pee pee".
Other expressions include "squirting" and "taking a leak", and, predominantly by younger persons for outdoor female urination, "popping a squat", referring to the position many women adopt in such circumstances. National varieties of English show creativity. American English uses "to whiz". Australian English has coined "I am off to take a Chinese singing lesson", derived from the tinkling sound of urination against the China porcelain of a toilet bowl. British English uses "going to see my aunt", "going to see a man about a dog", "to piddle", "to splash (one's) boots", as well as "to have a slash", which originates from the Scottish English for a large splash of liquid. One of the most common, albeit old-fashioned, euphemisms in British English is "to spend a penny", a reference to coin-operated , which used (Decimal Day) to charge that sum.
Some mammals urinate on themselves in order to attract mates during the rut or urinate on other individuals before mating with them. A male Patagonian mara, a type of rodent, will stand on his hind legs and urinate on a female's rump, to which the female may respond by spraying a jet of urine backwards into the face of the male. The male's urination is meant to repel other males from his partner while the female's urination is a rejection of any approaching male when she is not receptive. Both anal digging and urination are more frequent during the breeding season and are more commonly done by males.
A male porcupine urinates on a female porcupine prior to mating, spraying the urine at high velocity.
In 2010 in Washington state, a person who had died had received burns injuries on their body that were related to receiving an electric shock. It is thought that an electric current had traveled through their stream of urine and into their body. It is thought that the person had urinated into a roadside ditch and a live wire that was lying in the ditch gave the person an electric shock.
In 2014 in Spain, a person died while urinating on a lamp post when he received an electric shock, which may have traveled through the stream of urine and into his body.
The urine of animals of differing physiology or sex sometimes has different characteristics. For example, the urine of birds and reptiles is whitish, consisting of a pastelike suspension of uric acid crystals, and discharged with the feces of the animal via the cloaca, whereas mammals' urine is a yellowish colour, with mostly urea instead of uric acid, and is discharged via the urethra, separately from the feces. Some animals' (example: ') urine possesses a strong odour, especially when it is used to mark territory or
Felidae (1968). 9781489946584 ISBN 9781489946584 and scent-mark their territories using urine. Wolves mark their territories by urinating in a raised-leg posture and release preputial gland secretions in their urine. Male dogs mark their territories with urine more frequently than females.
Young cattle can be toilet-trained to urinate in a "latrine" where their urine can be collected for wastewater treatment, which could be used to reduce greenhouse gas emissions from the animals' urine in countries such as the Netherlands, the United States, and New Zealand.
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