The kidneys are bean-shaped organs responsible for filtering waste from the blood and producing urine. Each kidney comprises a renal capsule, cortex (outer layer), medulla (inner layer), pyramids, papillae, calyces (collecting cups), pelvis (funnel-shaped structure), and ureter (tube connecting to the bladder). Nephrons, the functional units of the kidneys, filter waste through the glomerulus and Bowman’s capsule, with tubules (proximal convoluted, loop of Henle, distal convoluted) involved in reabsorption and secretion. Blood vessels (renal artery, vein, capillaries) supply oxygen and nutrients to the kidney. Nerves regulate blood flow and urine production. The adrenal glands, located on top of the kidneys, secrete hormones that influence kidney function.