9. Glomerular filtration barrier

Question 1

Glomerula filtration barrier is responsible for

Answer 1

filtration of plasma according to size and net charge

Question 2

Glomerula filtration barrier is composed of ( and role of every component )

Answer 2

1. fenestated capillary endothelium –> SIZE BARRIER
2. fused basement membrane with heparan sulfate –> NEGATIVE CHARGE AND SIZE BARRIER
3. Epithelial layers consisting of podocyte foot processes–> NEGATIVE CHARGE BARRIER

Question 3

Components for size barrier and components for charge barrier

Answer 3

size : 1. fenestated capillary endothelium 2 . fused basement membrane
charge : 1. fused basement membrane 2. epithelial layers constisting of podocyte foot processes

Question 4

Charge barrier is los in ……. (in clinical presentation )

Answer 4

nephrotic syndrome –> 1. albuminuria 2. hypoproteinemia 3. generalized edema 4. hyperlipidemia

Question 5

• Glomerular fenestrated capillary endothelium filters plasma by ___ (size/charge); the fused basement membrane filters by ___ (size/charge).

Answer 5

Size; charge

Question 6

• The glomerular basement membrane contains the polysaccharide ____, which filters plasma with its ____ (positive/negative) charge.

Answer 6

Heparin sulfate; negative (blocks albumin filtration)

Question 7

• What are the three components of the glomerular filtration barrier? How does each contribute to the filtration function of the glomerulus?

Answer 7

Fenestrated capillary endothelium (size), fused basement membrane with heparan sulfate (negative charge), and epithelial layer (podocytes)

Question 8

• A patient presents with edema. Labs show albuminuria, hypoproteinemia, and hyperlipidemia. What has happened to the patient’s glomeruli?

Answer 8

This is nephrotic syndrome, resulting from loss of the charge barrier in the glomeruli (and therefore loss of protein, namely albumin)