URINARY SYSTEM, DRAWING. URINARY SYSTEM, DRAWING The urinary system is composed of two parts. The upper system contains two kidneys. The kidneys remove a type of waste called urea from the blood through a network of nephrons, glomerula, and renal tubules. Urea, water, and other waste substances form urine. Two ureter tubes carry urine from the kidneys to the bladder. The lower system contains the bladder, where urine is stored before its muscles contract, thus squeezing urine out of the bladd