Glomerular capillary endothelium

Figure 29.3. (A) Glomerular capillaries are positioned between two arterioles that regulate hydrostatic pressure and blood flow through the capillaries, thereby controlling glomerular filtration rate. (B) The glomerular basement membrane consists of three layers the capillary endothelium, the capillary basement membrane, and podocytes from epithelial cells of Bowman s capsule. The capillary basement membrane also contains three layers the lamina rara interna (blood side), lamina densa, and lamina rara externa (epithelial side). (From Guyton, A. C., and Hall, J. E. Textbook of Medical Physiology, 11th ed. Elsevier Saunders Company, Philadelphia, 2006. Reproduced with permission.)...

Capillaries in the Kidney. Filtration in the kidney occurs across a specialized capillary in the glomerulus. The glomerular capillary has several layers a monolayer of endothelial cells that interface with the flowing blood, an acellular basement membrane, and a filtration layer formed by glomerular epithelial cells. The endothelium is fenestrated that is, there are numerous... 

During the normal operation of mammalian kidneys, a large amount of fluid (about one fifth to one third of the plasma voliune) passes through the endothelium of the glomerular capillaries. This process may be regarded as ultrafiltration, resulting from an imbalance in transcapillary hydraulic (AP) and osmotic pressures (An). The flow rate J can be written as... 

The stimulation of mesangial cells to release and respond to tumor necrosis factor may accelerate the glomerular infiltration of polymorphonuclear leukocytes and monocytes. Indeed, the injection of tumor necrosis factor enhances glomerular damage in some forms of experimental glomerulonephritis [161]. Another important target is the vascular endothelium where an increase in the local production of tumor necrosis factor-a may result in the formation of capillary thrombi. An increase in plasma and urinary levels of two soluble tumor necrosis factor receptors has be found in patients with chronic renal failure [162]. 

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