PATHOLOGY

Detailed explanation-1: -The proximal tubule contributes to fluid, electrolyte, and nutrient homeostasis by reabsorbing approximately 60%–70% of the water and NaCl, a greater proportion of the NaHCO3, and nearly all of the nutrients in the ultrafiltrate.

Detailed explanation-2: -The proximal convoluted tubule is the part of nephron where majority of reabsorption occurs. Water, Na+, and K+ entering the nephron is reabsorbed in the proximal convoluted tubule and returned to the circulation.