The urinary system consists of the kidneys, ureters, urinary bladder, and urethra. The kidneys filter the blood and produce urine by removing waste and regulating fluid and electrolyte levels. The urine passes from the kidneys to the bladder through the ureters. The bladder stores urine until emptying through the urethra. The functional unit of the kidney is the nephron, which filters blood to form urine through glomerular filtration, reabsorption, and secretion. Together, these components work to maintain homeostasis by regulating fluid balance and removing waste from the body.