Urine (redirected from urine chromogens)

urine, clear, amber-colored fluid formed by the kidneys that carries metabolic wastes out of the body (see urinary system). As the blood circulates it collects excretory products from the tissues and these substances are separated from the blood by the kidneys and eliminated chiefly in the urine. The urine is then stored in the bladder and passes out of the body via the urethra. The amount passed depends on fluid intake and other factors. Urine is 95% water, in which are dissolved urea, uric acid, creatinine, and other waste products. Normal urine also contains small amounts of substances ordinarily utilized by the body, such as sodium, potassium, and calcium; these substances are excreted by the kidneys when excessive amounts are present in the bloodstream. Analysis of the urine is important in detecting diseases of the urogenital organs, as well as disorders of other body systems.

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urine

Liquid solution of metabolic wastes and other, often toxic, substances filtered from plasma. The fluid in the Bowman capsule at the start of each nephron is essentially plasma without the large molecules (e.g., proteins). The concentrated fluid (final urine) that exits the kidney consists of water, urea, inorganic salts, uric acid, creatinine, ammonia, and broken-down blood pigments, including urochrome, which makes urine yellow, plus any unusual substances not reabsorbed into the blood. This is then excreted. See also hematuria; urinalysis; urinary system; urination.

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Urine

An aqueous solution of organic and inorganic substances, mostly waste products of metabolism. The kidneys maintain the internal milieu of the body by excreting these waste products and adjusting the loss of water and electrolytes to keep the body fluids relatively constant in amount and composition. The urine normally is clear and has a specific gravity of 1.017–1.020, depending upon the amount of fluid ingested, perspiration, and diet. The increase in specific gravity above that of water is due to the presence of dissolved solids, about 60% of which are organic substances such as urea, uric acid, creatinine, and ammonia; and 40% of which are inorganic substances such as sodium, chloride, calcium, potassium, phosphates, and sulfates. Its reaction is usually acid (pH 6) but this too varies with the diet. It usually has a faint yellow color due to a urochrome pigment, but the color varies depending upon the degree of concentration, and the ingestion of certain foods (for example, rhubarb) or cathartics. It usually has a characteristic aromatic odor, the cause of which is not known. See Kidney, Urea, Uric acid, Urinary system