The kidneys are located between the T12 and L3 vertebrae in the retroperitoneal space. They are surrounded by a mass of fat (adipose capsule) and connective tissue called Gerota's fascia, which anchors them to the posterior parietal peritoneum. A fibrous capsule covers the kidney, except for its umbilical region. Surrounding each kidney are the renal capsules, comprising connective tissue, blood vessels, and lymphatic vessels. The concave part of the kidney houses the renal hilum, through which the renal artery, vein, lymphatic vessels, nerves, and pelvis pass. Every 45 minutes, plasma equal to the total plasma volume is filtered, and every 6 hours, an amount equal to the total body water is purified.Each kidney consists of three regions: cortex, medulla, and pelvis. The cortex lies beneath the fibrous capsule, with extensions forming renal columns that separate the medullary pyramids. The medulla contains the loop of Henle, vasa recta, and collecting ducts. Together, these structures support filtration and excretion functions essential to maintaining homeostasis.