The excretory system of man consists of a pair of kidneys, a pair of ureters, a urinary bladder, and a urethra. Kidneys: Appearance and Position: The kidneys are dark red, a bean-shaped organ about 10-13 cm long, 5-6 cm in breadth and 3-4 cm wide, weighing about 150-170 gm in adult male and 135-145 gm