urine - Composition, Other uses

A liquid or semi-solid solution produced by the kidneys in vertebrates (eg humans), Malpighian tubules in some invertebrates (eg insects), and nephridia in most invertebrates (eg annelids, molluscs). It consists of water, the end-products of metabolism (eg urea, uric acid, hydrogen ions), dietary constituents taken in excess (eg salts, vitamins), and foreign substances (eg drugs), or their derivatives. The volume and composition of urine is species-, diet-, and environment-specific, as well as being influenced by the state of health and the degree of physical activity. The expulsion of urine from the bladder is referred to as micturition.

This article is about the urine of animals generally.

Composition

Healthy urine is a clear aqueous solution, varying in colour from dark yellow to colourless depending on the dilution. Lighter urine color usually indicates higher water consumption. (Discuss)

As well as removing waste from the body, urine can be examined to determine many medical conditions concerning the bladder, kidneys, and even metabolic functions of the body.

Frequent urination and presence of sugar in the urine indicates the possibility of diabetes mellitus. Certain horomones excereted during pregnancy can also be found in urine, making urine analysis tests one of the most common pregnancy tests.

When there is blood in the urine you may need to see a doctor.

Urine may be tested with urine dips or examined under a microscope to find white blood cells or red blood cells. The presense of blood in the urine (known as hematuria) is abnormal and often points to infection or illness. Bacteria may also sometimes be found in urine, denoting an infection (usually in conjunction with white blood cells). Red blood cell casts will prove whether blood in the urine originates from the kidney.

Urine is typically composed of 95% water, and 5% solids.

Other uses

Some animals, such as cats and dogs, spray urine on objects to mark their territory or property.

Taking advantage of the scents of those animals' urine, some companies sell animal urine, usually coyote or fox, to cities and other organizations to prevent their trees from being stolen for use as Christmas trees. The scents of carnivore urine (bobcat, mountain lion, and wolf, in addition to coyote and fox) are also sold to the public in pelletized form to repel garden browsing by herbivores such as squirrels and rabbits, as well as deterring domestic or feral cats from marking territory, or catching birds, in gardens.

Many drug tests are done on urine.

In more rural times, urine was collected and used in the manufacture of gunpowder. Stale urine was filtered through a barrel full of straw and allowed to continue to sour for a year or more.

Urine has often been used as a mordant to help prepare textiles, especially wool, for dying.

Premarin is a hormone replacement product produced from the urine of a pregnant horse and is one of the most widely used hormone therapies.