Vascular-Tubular Relationships in the Mammalian Kidney

The mammalian kidney is an extraordinary complex structure because of its unique spatial organization in different zones that almost each nephron traverses along its course, and because of its highly elaborate vascular-tubular relationships. Reiner Beeuwkes made two independent movies, about the human and the dog kidney to illustrate these relationships. He used Microfil silicone rubber to illustrate the vascular supply of the different parts of the nephrons. For that purpose, he first injected the arterial vasculature as a whole through the renal artery. Then, using micropipettes and micromanipulators, he micro-injected Microfil of a different color into single nephrons in order to follow their course in the midst of the surrounding capillaries and vasa recta within the cortex and medulla. He comments himself the different observations beautifully presented in his movie.

The vascular system of the kidney comprises two capillary networks in series: the capillaries of the glomerular tuft that merge into an efferent arteriole, and the peritubular capillaries issued from the efferent arteriole of each glomerulus. The two movies shown below are intended to clarify some misconceptions about the kidney vasculature. Too many diagrams show a nephron with its loop of Henle entirely surrounded by vessels issued from the efferent arteriole of its own glomerulus. Reiner Beeuwkes explains how blood is supplied to the different parts of the nephron by different capillary beds. There are no "nephron units". Most segments of the nephrons are supplied by capillaries originating from the efferent arterioles of several different glomeruli located at different depths within the cortex.

These films were provided by Lise Bankir, PhD of INSERM (French Institute of Health and Medical Research) · Centre de Recherche des Cordeliers who received permission from Reiner Beeuwkes to provide these to the ISN Academy. Dr. Bankir converted the original 16mm films to video and then digital formats. The ISN Academy is grateful for Dr. Bankir's efforts and dedication to the field of Nephrology.