The metanephrogenic blastema arises from the caudal part of the nephrogenic cord (caudally to L3). Cells of the metanephrogenic blastema form a condensed metanephric cap around the ampulla. The ampulla flattens and forms two anchor wings. The tissue surrounding the two anchor wings thickens to form nephrogenic caps. A renal vesicle develops inside the nephrogenic cap under each wing. It then lengthens and forms a tubule. The tubule joins the wings of the anchor and, in doing so, becomes connected to the collecting tubule. The vesicle becomes invaginated to form a double-layered structure. The cells of the inner layer (visceral layer of the glomerular capsule) thicken, while those of the outer layer (parietal layer) flatten. The capsule is invaginated further by capillary loops (glomerulus). The glomerular capsule and the glomerulus together form the renal corpuscle. The renal corpuscle and the secretory tubule together make the nephron, which has thus developed from the metanephrogenic blastema and the capillaries.