Glomerular Structure and Function Flashcards
Review: When looking at the capillary loops of the glomerulus, what 3 main cell types will you see?
Endothelial cells.
Mesangial cells.
Podocytes (aka epithelial cells)
Review: How does charge affect the extent to which a large molecule is filtered?
Large cations are filtered more than large anions.
(albumin is negatively charged, and really isn’t filtered much.
You can remember that basement membrane is negatively charged, but that’s not the whole reason that anions are repelled.)
What function do nephrin-containing slit diaphragm complexes have other than functioning as a glomerular “sieve”?
They’re important for signaling / control of podocyte shape.
What, in mg, is the normal 24 hour urine protein content?
< 150 mg
Main protein to be secreted, not filtered, into the urine?
Tam-Horsfall protein
3 categories of mechanisms of increased urine protein?
Abnormal filtration.
Proximal tubule dysfunction (not enough reabsorption).
Protein overload.
3 proteins you find in the urine of a patient with abnormal glomerular filtration?
Albumin.
Transferrin.
IgG.
What specific histological finding correlates with proteinuria of glomerular origin?
Podocyte foot process effacement.
Name a few processes that can cause proximal tubular dysfunction (and with it proteinuria)?
Fanconi syndrome.
Allergic interstitial nephritis, sickle-cell disease, analgesic nephropathy, etc. etc.
Most common cause of protein overload proteinuria?
Plasma cell dyscrasia (e.g. multiple myeloma) -> Ig light chains aka paraprotein aka Bence Jones Protein
Would you see foot process effacement if for some strange reason you biopsied a patient with orthostatic or functional proteinuria?
Nope.
If you se >3.5g protein in 24 hours, where must the problem be?
(recall normal is < 150mg/24hr)
The glomerulus.
Should you ever ignore a positive urine albumin by dipstick?
No. Follow it up.
