Term
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Definition
| Produced by the glomeruli, closely mimics blood plasma sans cells and proteins. |
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Term
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Definition
125 ml/min
Greater in males than females
Declines with age |
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Term
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Definition
About 1L/min (20% of CO)
7x the blood supply of the brain. |
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Term
| RPF and hematocrit calculation |
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Definition
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Term
| Filtration barrier constituents |
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Definition
1. Capillary endothelial cells
2. Glomerular Basement Membrane (GBM)
3. Glomerular epithelial cells (podocytes) |
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Term
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Definition
| Concentration of solute in ultrafiltrate/concetration of solute in plasma |
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Term
| Factors influencing sieving coefficient |
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Definition
In order of importance
1. Solute size (smaller=more permeable, must be between 5500-44000)
2. Solute charge (+ charged is more permeable)
3. Solute shape (elastic and longitudinal is better than rigid and lobular)
When sieving coefficient=1, then solute is freely filtered. |
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Term
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Definition
Fructose polymer, plant origin.
Must be exogenously infused.
Filtered, but not reabsorbed or secreted.
Difficult to measure. |
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Term
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Definition
Endogenous product of muscle metabolism
Stable rate of production:
20-25 mg/kg in males
15-20 mg/kg in females
Easier to measure than inulin.
Slight secretion occurs, but not enough to throw off measurements except in cases of kidney disease where the GFR is lowered. |
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Term
| GFR calculation using creatinine |
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Definition
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Term
| Situations where creatinine measurements for GFR are less accurate |
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Definition
1. Low GFR (kidney disease)
2. Rapid flux in GFR (Kidney transplant)
3. Muscle injury (releases creatinine). |
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Term
| Levels of creatinine with removal of one kidney |
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Definition
1. GFR drops to half.
2. Production of creatinine stays the same while the excretion initially drops to half and then rises to normal levels.
3. Excretion rises back to normal levels because the plasma concentration of creatinine is doubled since excretion is halved initially. Since the filtered load=GFR (which is halved)multiplied by the plasma concentration of creatinine (which is doubled), it stays the same and excretion returns to normal levels. |
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Term
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Definition
Direction of flow determined by
Hydrostatic pressure in glomerular capillaries-Hydrostatic flow in Bowman's capsule (minor) + Oncotic pressure in glomerular capillaries - oncotic pressure in Bowman's space (minor).
Hydrostatic pressure decreases and oncotic pressure increases along capillary. |
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Term
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Definition
Hydrostatic pressure decreases and oncotic pressure increases along capillary.
If filtration is large (Large RPF), than hydrostatic pressure is always greater than oncotic pressure and filtration equilibrium is not reached (results in large GFR).
If filtration is small (low RPF), than hydrostatic pressure eventually is matched by oncotic pressure and filtration equilibrium is met (low GFR). |
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Term
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Definition
GFR/RPF
Equals amount filtered over amount going to efferent arteriole. |
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Term
| Constriction of afferent arteriole |
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Definition
| 1. GFR decreases since both glomerular capillary pressure and RPF both lower. |
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Term
| Constriction of efferent arteriole |
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Definition
1. Results in lowered RPF.
2. Results in pressure buildup in glomerular capillaries which increases GFR initially.
3. If resistance gets high enough, reduced RPF results in lowered GFR. |
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Term
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Definition
Relationship between solute that is filtered and amount secreted and reabsorbed.
Increased GFR results in increased absolute reabsorption and excretion.
Lowered GFR results in lowered absolute reabsorption and excretion. |
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Term
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Definition
| Vasoconstricts mainly efferent arterioles |
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Term
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Definition
| Main vasoconstriction at the medulla. |
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Term
| Vasodilators of the kidney |
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Definition
Atrial natriuretic peptide (results in afferent and efferent arteriolar vasodilation, increased cortical and medullary flow and GFR.
Modulated by dopamine and NO. |
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