Is the basement membrane selectively permeable?
Permeability characteristics have been determined for isolated ribbons of the basement membrane of the intestine ofAscaris suum. The results support the view that this basement membrane functions as a filter and selective barrier to diffusion of constituents of the worm’s body fluid.
What happens when glomerular basement membrane thickens?
Thickening of glomerular basement membrane (GBM) is a characteristic early change in diabetic nephropathy, and it strongly correlates with urinary albumin excretion.
Is the glomerular filtration membrane permeable?
The glomerular filtration barrier (GFB) is freely permeable to water, small- and midsized solutes in plasma, yet maintains considerable size and charge selectivity for proteins and larger molecules.
Why does glomerular basement membrane thicken?
As a rule, thickening of the glomerular basement membrane occurs soon after the onset of diabetes mellitus and gradually increases as clinically manifest diabetic nephropathy develops. Basement membrane thickening is accompanied by changes of the visceral glomerular epithelial cells (podocytes), which lie on the GBM.
Why is the glomerular basement membrane important?
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 can pass through the filtration membrane?
The resulting filtrate is a dilute solution that includes water, electrolytes, wastes, nutrients, and other molecules able to pass through the filtration membrane.
What can pass through the glomerular filtration membrane?
This complex “membrane” is freely permeable to water and small dissolved solutes, but retains most of the proteins and other larger molecules, as well as all blood particles. The main determinant of passage through the glomerular filter is molecular size.
What is the function of basement membrane?
The basement membrane (BM) is a special type of extracellular matrix that lines the basal side of epithelial and endothelial tissues. Functionally, the BM is important for providing physical and biochemical cues to the overlying cells, sculpting the tissue into its correct size and shape.
What forms the basement membrane of epithelia?
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).