URINARY SYSTEM, DRAWING. URINARY SYSTEM, DRAWING The urinary tract is divided into the upper urinary tract (two kidneys, each with a calyx and a ureter) and the lower urinary tract (bladder, urethra). Urine, produced continuously by the kidney, is collected in the calyx then conveyed to the bladder via a connecting tube, the ureter. Contraction of the muscles in the wall of the bladder causes urine to flow out of the body via the urethra. In women, the urethra is very short and opens into the