Structure of the Kidney The kidneys are bean-shaped organs located on either side of the vertebral column in the retroperitoneal space. They play a critical role in filtering blood, maintaining fluid and electrolyte balance, and excreting waste products in the form of urine. 1. External Structure of the Kidney A. Shape and Size: B. Location: C. Coverings: 2. Internal Structure of the Kidney A. Regions of the Kidney: B. Microscopic