What does a high concentration of NaCl in the renal tubule at the juxtaglomerular apparatus (JGA) most likely indicate?
a. insufficient NaCl reabsorption due to low GFR
b. excessive NaCl reabsorption due to low GFR
c. excessive NaCl reabsorption due to high GFR
d. insufficient NaCl reabsorption due to high GFR
-after glomerular filtration, NaCl is actively reabsorbed at many locations along the renal tubule. If the filtrate is moving through the tubule quickly, less reabsorption is possible, so more NaCl gets left behind. This means that at the JGA, the NaCl concentration within the filtrate will be high.