is a permanent kidney. metanephros development the metanephros develops from the ureteric bud, which is an outgrowth on the caudal part of the nephric duct, and the metanephrogenic blastema, which is part of the intermediate mesoderm surrounding the ureteral bud. the development of metanephros begins with the induction of a metanephrogenic blastema by the ureteric bud. while the kidney develops, the metanephrogenic blastema and ureteric bud reciprocally induce each other. growing into the mesoderm, the ureteric bud branches and transforms into a tree structure that will eventually become the ureter, renal pelvis, major and minor calyces, renal papillae, and collecting ducts. at the same time, at the tips of the collecting ducts, the mesoderm differentiates into epithelial cells that form nephron tubules (processes of epithelialization and tubulogenesis occur). vascular system of the kidney is also developed with the development of nephrons, with large vessels branching from the dorsal aorta. in some mammals, kidney organogenesis ends before birth, while in others it may continue for some time into the postpartum period (for example, in rodents it ends about a week after birth). when the formation of new nephrons (nephrogenesis) ends, the number of nephrons in the kidney becomes final. thus, after suffering damage, the kidneys of adult mammals cannot regenerate by forming new nephrons.