Term
| 3 layers of basement membrane |
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Definition
endothelial BM
lamina densa
containing type IV collagen and laminin
podocyte BM |
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Term
| Glomerular BM composition |
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Definition
glycoprotein heparin sulfate
negatively charged outer and inner layers |
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Term
| function of mesangial cells |
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Definition
phagocytosis
contraction/relax
secrete matrix that supports capallaries |
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Term
| proteins in filtration slit diaphragm |
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Definition
nephrin
CD2AP
determine flitration selectivity charactistics of filtration-slit diaphragm |
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Term
|
Definition
| zipper like in filtration slit diaphragm, filter < 20 nm diameter proteins |
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Term
| what prevents blood cells from leaving blood and entering bowman's capsule? |
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Definition
| diameter of fenestrae (~80nm) < diameter of blood cells (~8 micro meters) |
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Term
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Definition
[solute]BS / [solute]plasma
increased by:
small size
positive charge
not bound by plasma proteins |
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Term
| why is the coefficient of flitration for calcium ~ 0.5 |
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Definition
50% of total serum calcium is ionized and filterable
remainder is nondiffusable (chelated with anions 5% or bound to albumin 45%) |
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Term
| what happens to the small amounts of albumin that do get filtered into bowman's space |
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Definition
internalized by endocytosis in proximal tubule cells of S1 segment
via megalin and cubulin receptors
fuse with lysosomes --> degraded |
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Term
|
Definition
prescence of albumin in urine
indicates problem with glomerular filtration barrier |
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Term
| what is oncotic pressure (pi)? |
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Definition
osmotic pressure exerted by large proteins that are not readily filtered across capillary wall
accounts for 0.5% of plasma osmotic pressure
opposes filtration, favors reabsorbtion
capillary > interstitial or glomerular fluid |
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Term
| Glomerular capilaries vs nonrenal capillaries |
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Definition
hydrostatic pressure of GC and BS do not decrease across renal capillaries
oncotic pressure increases ONLY in GC |
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Term
| filtration equilibrium and disequilibrium |
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Definition
equilibrium: filtration forces = reabsorbion forcres prior to efferent arteriole
disequilibrium = filtration is still ongoing as plasma approaches efferent arteriole |
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Term
| impact of increased RPF on GFR? |
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Definition
Increased RPF increases GFR
GFR = 0.2*RPF |
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Term
| impact of increased RPF on FF |
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Definition
Increased RPF = decreased FF
FF = GFR/RPF |
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Term
|
Definition
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Term
| why does increased RPF decrease FF? |
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Definition
increased RPF decreases ability of capillary to filter water and therefore increase plasma oncotic pressure
increase in GFR<increase in RPF |
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Term
| does GCp change in direct porportion to changes in MAP? |
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Definition
No, resistances of afferent and efferent arterioles can be regulated by intrinsic and exrinsic mechanisms and therefore modify the relationship between MAP, GFR, and GCp
regulated by intrinsic mechanisms, angiotensin II, sympathetic nervous system, atrial natriuretic peptide (ANP) |
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Term
| factors regulating resistance in afferent and efferent arterioles (4) |
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Definition
sympathetic nervous system
angiotensin II
atrial natriuretic peptide
intrinsic mechanisms |
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