Definition: One of the paired organs that excrete urine, remove nitrogenous wastes of metabolism, reclaim important electrolytes and water, contribute to blood pressure control(renin-angiotensin system) and erythropoiesis (via erythropoietin production). The kidneys are bean-shaped organs about 11-cm long, 5-cm wide, and 3-cm thick, lying on either side of the vertebral column, posterior to the peritoneum, opposite the 12th thoracic and 1st–3rd lumbar vertebrae. In animals, the kidney has variable size and location.
Synonym(s): renTA, nephros
[A.S. cwith, womb, belly, + neere, kidney (L. ren, G. nephros)]