THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -Osmotic diuretics primarily inhibit water reabsorption in the proximal convoluted tubule and the thin descending loop of Henle and collecting duct, regions of the kidney that are highly permeable to water. As Na+ is reabsorbed in the proximal tubule, water normally follows and is reabsorbed by passive diffusion.

Detailed explanation-2: -Most of the solute reabsorbed in the proximal tubule is in the form of sodium bicarbonate and sodium chloride, and about 70% of the sodium reabsorption occurs here. Sodium reabsorption is tightly coupled to passive water reabsorption, meaning when sodium moves, water follows.

Detailed explanation-3: -As the collecting duct descends through the medulla, the increasing osmolarity in the surrounding interstitial fluid drives water reabsorption.

Detailed explanation-4: -Passive Water Reabsorption by Osmosis Is Coupled Mainly to Sodium Reabsorption. When solutes are transported out of the tubule by either primary or secondary active transport, their concentrations tend to decrease inside the tubule while increasing in the renal interstitium.