The kidneys, ureters, bladder, and urethra work together to remove waste products from the blood. The nephrons of the kidneys are involved in urine formation. The ureters, bladder, and urethra are responsible for eliminating urine from the body. The kidneys also play an important role in regulating blood cell production and blood pressure. Knowledge of the anatomy and physiology of the urinary system is important when collecting urine specimens, performing urinary testing, and assisting with cystoscopy.