Figure 4

Schematic representation of the typical pathological process of glomerular degeneration and sclerosis in glomerular diseases. A, structure of a normal corpuscle showing the Bowman's capsule binding the glomerular capillary tuft, mainly composed of endothelial and mesangial cells, podocytes and a basal membrane. The very proximal segment of the tubule is also depicted. B, an initial insult of undetermined nature produces a focal lesion leading to podocyte loss and activation of an inflammatory response involving circulating and resident inmmune system cells. C, superseding the normal repair process, a pathological response occurs, which commonly presents with mesangial and Bowman's capsule epiyhelial cell proliferation, limphocyte extravasation and infiltration, fibrosis, and podocyte loss. The ultrafiltration membrane becomes leakier and more permeable to proteins. D, fibrosis extends damage through the corpuscle by inducing apoptosis of epithelial cells and filling the spaces left by dead cells, all of which give rise to pathways connecting the Bowman's capsule with the interstitium through with the protein rich ultrafiltrate accesses other areas of the corpuscle and the tubules and causes further damage.