Urine: Encyclopedia - Urine

Urine

Urine is liquid waste excreted by the kidneys and is produced by the process of filtration. This waste is eventually expelled from the body in a process known as urination. Most commonly the excretion of urine serves for flushing waste molecules collected from the blood by the kidneys, and for the homeostasis of the body liquids; however, many species also use it for olfactory communication.

Urine and urination have many slang names, including "wee".

Urine - Composition

Urine is a transparent solution that is clear to amber in color, and usually is light yellow. It is the byproduct or waste fluid secreted by the kidneys, transported by the ureters to the urinary bladder where it is stored until it is voided through the urethra. Urine is made up of a watery solution of metabolic wastes (such as urea), dissolved salts and organic materials. Fluid and materials being filtered by the kidneys, destined to become urine, comes from the blood or interstitial fluid. The composition of urine is adjusted in the process of reabsorption when essential molecules needed by the body, such as glucose, are reabsorbed back into the blood stream via carrier molecules. The remaining fluid contains high concentrations of urea and other excess or potentially toxic substances that will be released from the body via urination. Urine flows through these structures: the kidney, ureter, bladder, and finally the urethra. Urine is produced by a process of filtration, reabsorption, and tubular secretion.

Urine contains large amounts of urea, an excellent source of nitrogen for plants. As such it is a useful accelerator for compost. Urea is 10,000 times less toxic than ammonia and is a byproduct of deamination (2 NH₃ molecules) and cellular respiration's (1 CO2 molecule) products combining together. Other components include various inorganic salts such as sodium chloride (the discharge of sodium through urine is known as "natriuresis".)

Urine - Function

Urination is the primary method for excreting chemicals and drugs from the body. These chemicals can be detected and analysed by urinalysis.

In cases of kidney or urinary tract infection (UTI) the urine will contain bacteria, but otherwise urine is virtually sterile and nearly odorless when it leaves the body. However, after that, bacteria that contaminate the urine will convert chemicals in the urine into smelling chemicals that are responsible for the distinctive odor of stale urine; in particular, ammonia is produced from urea.

Some diseases alter the quantity and consistency of the urine, (e.g. sugar in the urine is a sign of diabetes). Urine therapy is the use of urine topically or consumed, especially as recommended by the traditional Indian medicine, Ayurveda, under the name Amaroli.

Urine can give an indication of how well hydrated a person is. A hydrated person will commonly urinate a clear, water-like urine, whereas a dehydrated person may pass a darker yellow or brown urine as is often observed the morning after a night's drinking of large quantities of alcohol.

Urine - Other uses

Aztec physicians used urine to clean external wounds to prevent infection, and administered it as a drink to relieve stomach and intestine problems.

The ancient Romans used urine as a bleaching agent for cleaning clothes and even isolated reports as a teeth whitener (supposedly originating in what is now Spain).

In Siberia, to communicate with the spirits, the Koryak people drank the urine of another who has consumed fly agaric (an entheogenic mushroom that is occasionally fatally poisonous), or of one who has in turn drunk urine of like source. Sometimes, the urine of reindeer that had eaten fly agaric would even be drunk. The potency of the mushroom does not decrease significantly until around the seventh drinker, because the muscimol from fly agaric is essentially unaltered after being secreted from the kidneys. Not only does this conserve the mushrooms, but it also eliminates unpleasant side-effects caused by muscarine, which does not pass on through urine. Likewise, reindeer licked the ground where there is urine containing fly agaric from the religious ritual.

Urine has applications in gardening and agriculture as a [fertiliser]]. Gardeners often recommend a dilution of 10-15 parts water to one of urine for application to pot plants and flower beds during the growing season; pure urine can chemically burn the roots of some species. Urine typically contains more than 50% of the nitrogen and phosphorus and potassium content of whole sewage and is widely considered as good as or better than commercially-available chemical fertilisers or stabilised sludge from sewage plants. Urine is also used in composting to increase the nitrogen content of the mulch, accelerating the composting process and increasing its final nutrient values.

Urine is also being actively considered as a fertiliser for use in food crop agriculture in developed countries. Studies into its feasibility and safety usually indicate that it is an acceptable alternative to chemical fertilisers and stabilised sludge. However, the technology to implement its use on a large scale has not been developed or is considered too expensive. There are also concerns over its safety as regards the potential for transmitting infectious disease and refluxing xenobiotic compounds (associated with toilet cleaning products and prescribed drugs expelled in urine) in the human food chain. Proponents of adopting urine for this use usually claim the risks as being negligible or acceptable and point out that sewage causes more environmental problems when it is treated and disposed of compared with when it is used as a resource. Critics generally agree that more research is needed into how the resource is to be collected, processed and handled.

There are a limited number of individuals that use urine as a crop fertiliser. These include organic farming cooperatives and eco-villages where special urine-diverting toilets with collecting tanks are installed. Many of these also employ concepts such as greywater irrigation and the composting of fecal matter Many are the subject on ongoing feasibility studies sanctioned by governments and private organisations. These people generally reject safety concerns over its use on food crops provided that it is used with common sense. For example, application to fruit trees is considered safer than to bushes and especially root crops. It is also considered sensible to cease application at a safe interval before harvesting. However, the use of urine for this purpose is even rarer than its use on ornamental gardens.

In developing countries, the application of pure urine to crops is also rare. However, whole, untreated sewage, termed night soil is often applied to crops and is considered essential. It is worth noting that this practice is not new and has been applied, along with crop rotation schemes, for thousands of years.

In Japan, urine used to be sold to farmers who would process it into fertilizers.

Shipwrecked or people otherwise adrift at sea for long periods often resort to drinking their urine when no rainwater is available, seawater being unsuitable. People stranded in deserts often also drank urine to prevent life-threatening dehydration from setting in. However, this desperate measure achieves little to delay death from thirst, particularly if it causes vomiting.

The use of urine as a medical treatment or daily health regimen is uncommon. Purported beneficiaries of the 'urine cure' include Mohandas Gandhi, Jim Morrison, and Steve McQueen. Its medicinal properties have been observed and is also used in China as a part of holistic medicine.

During World War I, Canadian soldiers without gas masks during a gas attack urinated on cloth and wore the cloth over their mouths and noses.

In recent times, the Port-a-John corporation of Utica, Michigan, USA has developed a filter to collect medically significant proteins from users of their chemical toilets.

Urine - History

The yellow color of urine was previously thought to come from gold. Alchemists spent much time trying to extract gold from urine, and this led to some interesting discoveries such as white phosphorus, which was discovered by the German alchemist Hennig Brand in 1669 when he was distilling fermented urine. In 1773 the French chemist Hilaire Rouelle, discovered the organic compound urea by boiling urine dry.

See also

• Urolagnia, an attraction to urine
• Urine therapy
• Drinking urine

Adapted from the Wikipedia article "Urine", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki