Glomerular filtration barrier

[anbuitachi]

What is the most significant factor for size barrier for glomerular filtration? Uworld mentioned that the slit diaphragm and GBM is very important for size selection. First aid didn't mention this.. but did mention endothelium fenestration as the size barrier... Wikipedia showed that GBM lamina densa is size barrier....
Which is the most important?

And also which is the most important charge barrier. I know heparan sulfate does it.. but where is the key location of the heparan sulfate that prevents most of the charges from filtering?

Thanks!

---

Members don't see this ad.

 

[g8orlife]

What is the most significant factor for size barrier for glomerular filtration? Uworld mentioned that the slit diaphragm and GBM is very important for size selection. First aid didn't mention this.. but did mention endothelium fenestration as the size barrier... Wikipedia showed that GBM lamina densa is size barrier....
Which is the most important?

And also which is the most important charge barrier. I know heparan sulfate does it.. but where is the key location of the heparan sulfate that prevents most of the charges from filtering?

Thanks!

What is the most significant factor for size barrier for glomerular filtration?
Rx stated that the capillary endothelium's size barrier is ~400 Angstroms & the epithelial layer of podocyte foot processes is ~ 40 Angstroms.
So, the podocyte foot processes have the smallest size (but you can argue that the capillary endothelium is the most significant since it is the first barrier that limits filtration)

Which is the most important?
This answer depends on what you're talking about. Let's use albumin as an example. Rx stated that albumin is ~36 Angstroms and has a negative charge. Thus, it is small enough to fit thru both size barriers that I listed above, but the negative charge of the fused BM limits its filtratration (see next answer for more details)

where is the key location of the heparan sulfate that prevents most of the charges from filtering?
This is in FA. It's located within the fused basement membrane

 

[anbuitachi]

Thank you!