TUBULO-VASCULAR RELATIONSHIPS IN DEVELOPING KIDNEY

  • 1 January 1977
    • journal article
    • research article
    • Vol. 123  (APR) , 487-500
Abstract
Changing relationships between tubules and blood vessels of the kidney during the first 42 days of postnatal life were studied in 60 Wistar rats. Methods used included normal histological techniques combined with i.v. injections of Indian ink. At birth, only the juxtamedullary glomeruli were differentiated, whose loops of Henle grew down into the medulla around the collecting ducts which were already present. Radially arranged tubulo-vascular units were formed, each consisting of collecting ducts, long loops of Henle and a capillary network. As new glomeruli develop in the nephrogenic zone, their (short) loops of Henle were added to the periphery of the units until only small spaces occupied by loose connective tissue were left between the units. When the vasa recta developed and linked up with the juxtamedullary efferent arterioles and the arcuate veins, they were formed in connective tissue of the spaces and eventually form the characteristic vascular bundles of the outer medulla. The vascular bundles were not the true architectural units of the medulla but developed secondarily in between the tubulo-vascular units. The processes of development explained the complex relationships between tubules and vessels in adult vascular bundles in which ascending vasa recta at the periphery of the bundles were closely related to descending short loops of Henle; long loops and collecting ducts were arranged in between the bundles.