How is the excretion of water and sodium regulated in the kidney?
Regulation of water and sodium excretion in the kidney
The kidney is capable of eliminating more or less concentrated urine depending on the individual's hydration status.
The hormone antidiuretic hormone (ADH) acts on the collecting duct, making it more or less permeable to water, thus conditioning a greater or lesser reabsorption of the 15% of water that reaches this segment and, therefore, a more or less diluted urine.
The reabsorption of sodium in the proximal tubule creates an osmotic gradient that induces the passive reabsorption of water and also urea.
The secretion of potassium and hydrogen ions in the distal tubule contributes to the acidification of urine.
The kidney is capable of regulating the excretion of water and sodium according to the individual's hydration status through hemodynamic and hormonal mechanisms.