What is the function of the glomerular basement membrane?
What is the function of the glomerular basement membrane?
The glomerular basement membrane (GBM) is the next critical component of the glomerular filtration barrier. It provides a scaffold that supports the physiological function of the glomerular endothelium and podocytes. Severe structural abnormalities of the GBM result in enhanced albumin leakage.
What is the glomerular ultrafiltration barrier?
In renal physiology, ultrafiltration occurs at the barrier between the blood and the filtrate in the glomerular capsule (Bowman’s capsule) in the kidneys.
What is the glomerular basement membrane components?
Like all basement membranes, the GBM consists mainly of laminin, type IV collagen, nidogen, and heparan sulfate proteoglycan. However, the GBM is unusually thick and contains particular members of these general protein families, including laminin-521, collagen α3α4α5(IV), and agrin.
What is glomerular capillary membrane?
The glomerular capillaries are lined by a fenestrated endothelium that sits on the glomerular basement membrane, which in turn is covered by glomerular epithelium, or podocytes, which envelops the capillaries with cellular extensions called foot processes. In between the foot processes are the filtration slits.
What is podocyte cell?
Podocytes are specialized epithelial cells that cover the outer surfaces of glomerular capillaries. Unique cell junctions, known as slit diaphragms, which feature nephrin and Neph family proteins in addition to components of adherens, tight, and gap junctions, connect adjacent podocyte foot processes.
What cells produce basement membrane?
The basement membrane (BM) is a fibrous matrix composed primarily of glycoproteins, type IV collagen, and laminin that are secreted by the epithelial cells (Ryerse, 1998).
What are glomerular capillaries made of?
The glomerular capillary wall or filtration barrier consists of three components: the capillary endothelium, basement membrane, and visceral epithelium (Fig. 2-2). The glomerulus is a unique vascular structure consisting of a capillary bed interposed between two arterioles: the afferent and efferent arterioles.
What is unique about glomerular capillaries?
Glomerular capillaries are internally lined by endothelial cells that are in contact with the bloodstream. A unique feature of glomerular endothelial cells is their fenestrations—holes in the cell that permit passage of fluid across the glomerular capillary wall.
What is the basement membrane of the glomerular?
Basement Membrane. The glomerular basement membrane is a trilaminar membrane consisting of the lamina densa in the middle, lamina interna next to the endothelial cells, and lamina externa next to the podocytes. The podocytes and endothelial cells secrete proteins to make up the basement membrane.
What is anti-glomerular basement membrane (GBM)?
Anti-glomerular basement membrane (GBM) is an antibody that reacts with glomerular basement membranes and which may cross-react with alveolar basement membranes. It is useful in the diagnosis of Goodpasture’s syndrome. Anti-GBM may be detected by IIF, direct immunofluorescence, immunometric assays, multiplex flow immunoassay or western blot.
What is the pathophysiology of glomerular basement membrane thickening?
Thickening of glomerular basement membrane (GBM) is a characteristic early change in diabetic nephropathy, and it strongly correlates with urinary albumin excretion. GBM thickening is then followed by glomerular mesangial expansion which is a hallmark of diabetic nephropathy and eventually leads to decline in renal function.
What is the function of the basal lamina of the glomerulus?
The glomerular basement membrane of the kidney is the basal lamina layer of the glomerulus. The glomerular endothelial cells, the glomeular basement membrane, and the filtration slits between the podocytes perform the filtration function of the glomerulus, separating the blood in the capillaries from the filtrate that forms in Bowman’s capsule.