The urinary system consists of the kidneys, ureters, bladder, and urethra, with the kidneys filtering waste from the bloodstream to produce urine, which travels through the ureters to the bladder for storage and then exits the body through the urethra. The kidneys remove excess water, salts, and urea from the bloodstream, with the renal arteries carrying blood into the kidneys and the renal veins carrying blood away from the kidneys back to the heart. Damage to the kidneys can result in renal disease, which can be acute from trauma or chronic over a long period of time.