Nephron (from Greek νεφρός [nephros] meaning "kidney")'s the basic structural and functional unit of the kidney. Its chief function's to regulate the concentration of water and soluble substances like sodium salts by filtering the blood, reabsorbing what's needed and excreting the rest as urine. A nephron eliminates wastes from the body, regulates blood volume and blood pressure, controls levels of electrolytes and metabolites, and regulates blood pH. Its functions… (More on Nephron)