Question

22 multiple choice 2 points as the nephron loop descends through the kidney tissue (from the cortex to the medulla), the tissue becomes saltier. why is this concentration grad aldosterone travels down its concentration gradient in the proximal loop osmotic pressure in the loop determines glomerular filtration capillary hydrostatic pressure determines aquaporin placement counter - current flow assists in water reabsorption

Explanation:

The counter - current multiplier system in the nephron loop creates a concentration gradient in the kidney medulla. As the loop descends, the tissue becomes saltier due to the active transport of sodium and chloride ions out of the ascending limb and the passive movement of water out of the descending limb, which is part of the counter - current flow mechanism that aids in water reabsorption. Aldosterone acts mainly on the distal convoluted tubule and collecting duct, not the proximal loop for this gradient formation. Osmotic pressure in the loop is related to reabsorption, not directly to the gradient in the medulla for glomerular filtration. Capillary hydrostatic pressure is related to filtration at the glomerulus, not aquaporin placement for this gradient.

Answer:

Counter - current flow assists in water reabsorption