PATHOLOGY

Detailed explanation-1: -The descending limb of loop of Henle is permeable to water but almost impermeable to electrolytes. This concentrates the filtrate as it moves down. Thus filtrate at the base of loop is hypertonic. The ascending limb is impermeable to water but allows transport of electrolytes actively or passively.

Detailed explanation-2: -Osmolarity changes in the Loop of Henle.-Osmolarity (the relative amount of solutes) increases in the descending loop because it’s permeable to water, but no solutes leave.

Detailed explanation-3: -Osmolarity Changes The filtrate osmolarity drops to 1200 mOsm/L as water leaves through the descending loop of Henle, which is impermeable to ions. In the ascending loop of Henle, which is permeable to ions but not water, osmolarity falls to 100–200 mOsm/L.