2. Supplied with blood by renal artery; after passing through the kidney, blood is returned to the heart by the renal vein

3. Forms urine, which is transported by the ureter to the bladder; excreted from the body at suitable intervals via the urethra (micturition reflex)

Note: the ureter, bladder, and urethra do not change the composition of urine; when urine leaves the kidney, its composition is fixed

Note: problem of urine retention by bladder; use of ultrasonic "BladderScan"