A network of thin-walled blood capillaries that branch from the efferent arterioles leaving the glomerulus in juxtamedullary nephrons of the kidney in mammals and birds. The vasa recta forms a series of interconnected U-shaped loops around the loop of Henle and its vessels eventually coalesce into venules that ultimately drain into the renal vein. Water from the kidney medulla is reabsorbed by the vasa recta during the formation of urine.