Sodium, Chloride, and Water Balance
- Sodium and water balance are intimately related; chloride levels are generally proportional to change in sodium levels.
- Water balance is regulated by the sensation of thirst and by antidiuretic hormone (ADH), which is secreted in response to by an increase in plasma osmolality or a decrease in circulation blood volume.
- Sodium balance is regulated by aldosterone, which increases reabsorption of sodium from the urine into the blood by the distal tubule of the kidney.
- Renin and angiotensin are enzymes that promote secretion of aldosterone and thus regulate sodium and water balance.
- Atrial natriuretic hormone also is involved in decreasing tubular reabsorption and promoting urinary excretion of sodium.