Kidney: Glomerular Membrane Flashcards
Glomerular Membrane seperates
Blood in capillaries from filtrate in bowman’s capsule
Enumerate Layers of Glomerular Membrane
- Capillary endothelium
- Basement membrane
- Podocytes
Describe properties of Capillary endothelium of Glomerular Membrane
- Not Barrier for filtration of proteins (passes proteins)
- Has relativeley large fenestration/ perforations/ holes (70-90 nm)
Describe properties of Basement membrane of Glomerular Membrane
- made up of Meshwork of Collage
- with negatively charged proteoglycan fibrils
- Major filter of Proteins
Describe properties of podocytes of Glomerular Membrane
- Epithelial cells that line outer surface of glomerular membrane
- Have many pseudopodia that interdigitate to form slit pores (25 nm)
Total Surface area of glomerular membrane
0.8 m2
Define Mesengial cells of glomerular membrane
Stellate contractile cells between basement membrane & endothelium at bifurication of the capillaries
Function of Mesengial cells
Regulation of GFR:
* they have receptors for Vasoactive substances
* Contraction of Mesengial cells decreases Surface area which decreases filtration (and vice versa)
Immune function: Secretes cytokines
Highly selective permeability of Glomerular Membrane is determined by
- Size of Solutes
- Charge of Solutes
According to size, which substances are filtered through glomerular membrane and which are not
Freely filtered:
* Neutral Substances less than 4nm (substance that are not neutral: Na, glucose)
Not filterd: more than 8nm
According to Charge of Solutes, which substances are more easily filtererd
positively charged Molecules
Explain why Albumin glomerular concentration is 0.2 % of plasma concentration, despite having diameter of 7nm
Due to its Negative charge
Explain why Kidney Diseases Cause Albuminuria
- The negativity of Basement membrane is lost
- which causes Protein to be filtered through
- such as Albumin
