The illustration shows left and right kidney, adrenal glands, ureter, inferior vena cava with renal veins and aorta with renal arteries. The kidney is a paired, bean-shaped organ that is located in the retroperitoneum. They have an excretory function and thus influence blood pressure and acid-base balance. The kidneys are located near the spine on the psoas muscle. The kidney is divided into the marrow area and cortical zone. The kidney is vital for metabolic end product excretion and blood pressure regulation. Moreover, Erythropoitin (EPO) is formed in the kidneys.The adrenal glands, are a pair of endocrine glands. The cortex is divided into zona glomerulosa, fasciculata and reticularis. In each of these zones, some of the 40 different hormones that are produced by the adrenal cortex are synthesized. The adrenal medulla is where catecholamines such as adrenaline are produced.