PATHOLOGY MCQ
URINARY SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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water ____ urea
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salt ____ water
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water ____ salt
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urea ____ water
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Detailed explanation-1: -Reabsorption of Na+ in the thick ascending limb of Henle’s loop (TAL) occurs through (1) transcellular pathways involving the Na+-2Cl−-K+ cotransporter in the apical membrane and (2) paracellular pathways driven by the lumen positive transepithelial potential difference.
Detailed explanation-2: -The descending portion of the loop of Henle is extremely permeable to water and is less permeable to ions, therefore water is easily reabsorbed here and solutes are not readily reabsorbed.
Detailed explanation-3: -The loop of Henle serves the crucial function of creating an ion gradient in the renal medulla by fluctuating the reabsorption of water and ions. In the descending limb, water is removed from the filtrate and enters into the interstitium, resulting in a highly concentrated filtrate.