THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -Because the vasa recta contains mostly large proteins and red blood cells (as the other contents have been filtered in the glomerulus), it is very concentrated and therefore water moves into it via osmosis.

Detailed explanation-2: -Water and substances that are reabsorbed are returned to the circulation by the peritubular and vasa recta capillaries. It is important to understand the difference between the glomerulus and the peritubular and vasa recta capillaries.

Detailed explanation-3: -Water is reabsorbed by osmosis in the water-permeable descending limb, but not in the ascending limb. This water reabsorption in the water-permeable descending limb can occur because the descending limb dips down toward, or into, the renal medulla, where the osmolarity of the interstitial fluid increases.