The<unk>  is the organ system that produces, stores, and eliminates urine. In humans it includes two kidneys, two ureters, the bladder, and the urethra. The analogous organ in invertebrates is the nephridium (in animals).
Urinary system
Central nervous system
Enteric nervous system
Musculoskeletal system
Circulatory system
Lymphatic system
Female reproductive system 
Lymph vascular system