Urine is a clear, yellowish fluid removed from the bloodstream by the kidneys.  Urine is made mostly of water, however it contains the waste products of metabolism which occurs in every cell of the body!  The major components of urine are water, salts, urea, nitrogenous waste products, and ions.

Water - Urine is made mostly of water.  Almost all of the water that a person drinks is absorbed into the bloodstream.  The kidneys must regulate the amount of water in the body by removing the excess and excreting it in urine.

Urea -  Cells throughout the body create a toxic substance called urea when amino acids are converted to energy.  Urea leaves the cells and enters the bloodstream.  The kidneys filter out urea and allow it to be excreted into the urine.

Nitrogenous wastes - more byproducts of metabolism in cells.  Ammonia, for example, must be removed from the blood.  Otherwise, a high blood ammonia level can cause neurologic problems and even death if not corrected quickly.

Electrolytes - Electrolytes may be found combined as salts or alone as ions.  The kidneys help regulate blood levels of electrolytes such as sodium, calcium, potassium, and chloride.  Electrolye abnormalities can cause muscle, heart and nerve dysfunction.