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32 Cards in this Set
- Front
- Back
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What is the normal plasma osmolarity?
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285-295 mOsm/L
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What is the range of urine osmolarity?
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50 mOsm/L-> 1400 mOsm/L
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can the kidneys regulate water and solute excretion separately?
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yes they can! like pimps!
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Is there Na+ reabsorption in the loop of henle?
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yes there is, 25% of total. and it is active
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Is there water reabsorption in the loop of henle?
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yes there is, 15% of total. this is passive and linked to solute movement
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is there Na+ reabsorption in the Distal tubule and Collecting tubule?
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yes there is. 8% of total, and is subject to control by aldosterone
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Is there water reabsorption in the distal tubule and colllecting duct?
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yes there is, 20%. it is passive and regulated by ADH
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Where does the counter current multiplier occur?
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this takes place in the long loop of henle
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What is the function of the osmotic gradient from cortex to medulla in interstital space?
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this is used to remove water from urine in the collecting duct
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How does the descending limb of henle affect NaCl and H2O?
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NO active transport of NaCl
VERY permeable to water |
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How does the ascending limb of henle affect water and NaCl?
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This is impermeable to water
actively transports NaCl OUT of loop of henle into interstitum. (reabsorbtion) |
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What happens to fluid as it flows down the descending limb of henle?
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fluid is progressively concentrated
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What happens to fluid as it flows up the ascending limb?
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it is progressively diluted (by actively pumping NaCl out)
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what is the essential component in the countercurrent multiplier?
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active transport
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What is the purpose of the Na+,K+, 2Cl transporter? where is it found? What affects it?
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this is found in the ascending thick limb of henle.
This is used to pump Na+ OUT of the tubular fluid (diluting it). Lasix blocks this (duiretic), and ADH stimulates this (to reabsorb Na+) |
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What doesnt renal blood flow wash away the solutes in the medullary ISF?
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The countercurrent exchange by the Vasa Recta "protects" the corticomedullary gradient
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How does the vasa recta help the loop of henle?
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this is a passive process where the vasa recta matches the osmolatiry of the intersitum around it. allowing h2o and NaCl to flow in and out as needed
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What does urea contribute to?
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hyperosmotic renal ISF and concentrated urine
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How much of medullary ISF osmolarity is due to urea?
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about 1/2
so a high protein diet increases the concentrating abilities of the kidneys. |
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What controls the permeability of urea? in what segment of the nephron?
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ADH increases the permeability!
this is ONLY in the inner medullary portion of the collecting duct |
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How is the early portion of the distal convoluted tubule different than the later?
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the early portion is NOT permeable to water. does NOT contain Na+ K+ 2CL. (called the diluting segment)
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What transporter is found in the early distal convoluted tubule? what is it sensitive to?
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There is a NaCL transporter found in the early distal convoluted tubule. This is sensitive to Thiazide. Thiazide blocks NaCl reabsorption
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What are the two types of cells in the LATE distal tubule and collecting duct? what do they do?
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Principal cells: Reabsorb Na+, but secrete K+ (aldosterone acts here)
Intercalated cells: Secrete H+, reabsorb K+ |
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What cells in the late distal tubule and collecting duct are sensitive to aldosterone?
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Principal cells
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is the early distal convoluted tubule permeable to water?
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NO it is not
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What controls the Water and urea permeability in the collecting duct?
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Vasopressin/ADH
(without ADH, collecting duct is IMPERMEABLE to water and urea) |
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What does ADH do in the collecting duct?
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this causes the insertion of aquaporins causing water to be pulled out- concentrating urine
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Where is 60-80% of NaCl and water reabsorbed? What is the osmolarity of the fluid?
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This is in the proximal tubule
fluid remains isosmotic |
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What happens to water in the descending limb of LOH? osmolarity of the fluid?
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Water is reabsorbed
the fluid is now hyperosmotic |
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What happens to salt in the ascending limb of LOH? osmolarity of the fluid?
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Salt is active reabsorbed
the fluid is now hyposmotic |
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What happens to water and salt in the EARLY distal tubule? osmolarity of the fluid?
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NO WATER reabsorption
some NaCl reabsorption (sensitive to chlorothiazide) Fluid remains hyposmotic |
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What happens to Na+ and Water in the late distal tubule and collecting ducts?
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Na+ reabsorption is regulated by aldosterone
water reabsorption is regulated by ADH (high ADH, hyperosmotic, LOW ADH hyposmotic) |
