Topological analysis of the three-dimensional structure of the human renal glomerulus using a computer-aided reconstruction system.

A quantitative topological analysis of human renal glomerular capillaries reconstructed from serial sections was performed with the aid of a computer system. The peripheral portions of five glomeruli from each of the subcapsular, midcortical, and juxtamedullary zones were reconstructed, each portion corresponding to about one-sixth the diameter of a glomerulus. Statistically, there was no significant difference in the cycle rank (number of independent cycles) of the glomerular capillary network per unit volume of glomerular capillaries or Bowman's capsule among the three renal zones. It was proved that, irrespective of the location of the glomerulus, the glomerular capillary network possessed a larger cycle rank as the volume of the glomerular capillaries or Bowman's capsule increased. This finding strongly suggests that the mean cycle rank per single glomerulus is largest in the juxtamedullary zone.