(i) Kidney: Kidneys filter the blood and remove the nitrogenous wastes and other toxic substances from the blood and are involved in urine formation.
(ii) Ureter: These are a pair of muscular tubes which are thin and come out of the kidneys. The main function of the ureters is to pass urine from the kidney to the urinary bladder.
(iii) Urinary bladder: This is a muscular sac-like structure responsible for temporary storage of urine.
(iv) Urethra: It is connected to the urinary bladder and expels urine from the body.