What organs are included in the urinary system? What functions do they perform?

The urinary system removes metabolic products from the body, primarily urea; excess water and salt, as well as harmful substances that have entered the bloodstream from the intestines. The excretory system is formed by:
a) two kidneys – in their nephrons there is a filtration of blood and the formation of urine;
b) two ureters – pass urine into the bladder;
c) the bladder – stores urine;
d) urethra – periodically removes urine outside.