Urine is the fluid excreted by the kidneys of vertebrates to clear the bloodstream of excess water and metabolic by-products including urea, uric acid, and creatinine.
Sample of human urine
Tigers spray small quantities of urine to mark their territories.
Urine containing uric acid crystals under the microscope
Medical experts have long connected urine colour with certain medical conditions. A medieval chart showing the medical implications of different urine color
Urea, also called carbamide, is an organic compound with chemical formula CO2. This amide has two amino groups joined by a carbonyl functional group. It is thus the simplest amide of carbamic acid.
Urine
…Urine is the fluid excreted by the kidneys of vertebrates to clear the bloodstream of excess water and metabolic by-products including urea, uric acid, and creatinine. In mammals, urine travels from the kidneys via the ureters to the bladder for storage until urination. Placental mammals…
Structure of [Fe(urea)6]2+ showing intramolecular hydrogen bonds. Color code: blue = N, red = O.
A plant in Bangladesh that produces urea fertilizer
Urea plant using ammonium carbamate briquettes, Fixed Nitrogen Research Laboratory, ca. 1930