The illustration shows left and right kidney, adrenal glands, ureter, vena cava with renal veins and aorta with renal arteries in front of a white background. The kidneys are a bean-shaped pair of retroperitoneal organs, located on the psoas muscle next to the spine. The kidneys are divided into medulla and cortex. They excrete metabolic waste products and regulate the blood pressure as well as the acid-base balance. They also produce erythropoietin (EPO). The adrenal glands are a pair of endocrine glands. Their cortex contains the glomerulous, fasciculate, and reticular zone, where 40 different adrenocortical hormones are produced. Katecholamines like adrenalin are produced by the adrenal medulla.