Kidney and adrenal gland, artwork. The kidney is one of a pair of organs that form urine by filtering out waste products from the blood. The urine travels down the ureter (tube, lower right) to the bladder (unseen), where it is excreted. The adrenal gland sits on top of the kidney. This endocrine gland secretes a variety of hormones. These include adrenaline (epinephrine), the body's stress hormone, and corticosteroid hormones, which affect carbohydrate metabolism and the sex glands.