Term
| Where does aldosterone work in the nephron? |
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Definition
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Term
| What 3 factors determine K excretion? |
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Definition
| Aldosterone levels, HCO3 levels, and distal tubule flow |
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Term
| Where and how do loop diuretic work? |
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Definition
| They work in the ascending loop; they inhibit the Na/K/2Cl symporter so they aren't absorbed into the medulla; without this gradient, H20 stays in the tubule and is excreted |
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Term
| Where/how do thiazides work? |
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Definition
| Early distal tubule; they inhibit Na reabsorption |
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Term
| Where/how do K-sparing diuretics work? |
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Definition
| They inhibit aldosterone in the late distal tubule/collecting ducts (mostly the collecting duct) |
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Term
| Where/how do carbonic anhydrase inhibitors work? |
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Definition
| They inhibit carbonic anhydrase in the proximal tubule. Usually, HCO3 in the tubule binds with a free H+ via C.A. to form carbonic acid, which then dissociates into H20 and CO2. The free H+ is in the tubule because of a Na/H exchange; the Na is absorbed, the H is secreted. If CA is inhibited, the free H+ in the tubule stays there, and there is no need for the Na/H exchange. Therefore, Na stays in the tubule instead of being exchanged for H+, and a diuresis ensues. Also, acidosis ensues because usually the CO2 formed by CA crosses out of the tubule and into the medulla, where it joins with water, forming carbonic acid and then H+ and HCO3. This HCO3 is usually reabsorbed; however, when CA is inhibited, it is not, and you lose your HCO3 and become acidotic. (see page 288 of memory master) |
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Term
| Where/how do osmotic diuretics work? |
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Definition
| They are completely filtered in the glomerulus; therefore they stay in the tubule, increasing osmolarity and preventing H20 and Na from being reabsorbed; K excretion increases due to increased flow through the distal tubule |
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Term
| What test is used to differentiate pre-renal vs renal failure? |
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Definition
| Fractional Excretion of Filtered Na (it will be high in renal failure since the kidney is unable to reabsorb the Na so large amounts of it remain in the urine) |
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Term
| What is the best test of renal reserve? |
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Definition
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Term
| What is the most common cause of death in the chronic renal failure patient? |
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Definition
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Term
| Which hormone controls extracellular fluid volume? |
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Definition
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Term
| Which hormone controls extracellular Na concentration? |
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Definition
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Term
| Where is filtered glucose usually reabsorbed? |
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Definition
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Term
| Which region of the kidney is most vulnerable to ischemia? |
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Definition
| Inner stripe of outer medulla |
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