initially a pronephros develops in the posterior wall of the coelomic cavity
this is replaced by the mesonephric system, which comprises a long ridge of mesoderm, the mesonephros, with its duct, the mesonephric (Wolffian) duct.
the mesonephros itself then disappears except that in men some of its ducts become the efferent tubules of the testis
at the lower end of the mesonephric duct a diverticulum develops - this becomes the ureteric bud, on top of which develops a cap of tissue = metanephric mesenchyme
this gives rise to glomeruli and the proximal part of the renal duct system
the ureteric bud forms the ureter, renal pelvis, calyces and distal ducts
the mesonephric duct atrophies in women but the remnants persist in the broad ligament as the epoophron, paraooron and ducts of gartner. in men it gives rise to the epididymis and the vas def
the kidney originally develops in the pelvis of the embryo and then migrates cranially, acquiring a progressively more proximal arterial blood supply as it does so.
This complex developmental process explains the high freq with which congenital anomalies of the kidney, the ureter and the renal blood supply are found