Interdisciplinary Note (30 of 36)
Secretion and reabsorption of various solutes throughout the nephron.
Secretion of H+ occurs in both the proximal and distal convoluted tubules, essential to pH regulation. Excess K+ may also be secreted from the distal convoluted tubule and the collecting duct. The reabsorption of HCO3-, and the exchange of NH4+ for K+ are also important means of regulating pH.