First, blood from the renal arteries and their subdivisions is delivered to the glomeruli.The glomeruli form an ultrafiltrate, nearly free of protein and blood elements, which subsequently flows into the renal tubules.The tubules reabsorb and secrete solute and/or water from the ultrafiltrate.The final tubular fluid, the urine, leaves the kidney, draining sequentially into the renal pelvis, ureter, and bladder, from which it is excreted through the urethra