hormonal and metabolic disorders
Overview of Sodium's Role in the Body
Controlling blood volume
The total amount of sodium in the body affects the amount of fluid in blood (blood volume) and around cells. The body continually monitors blood volume and sodium concentration. When either becomes too high, sensors in the heart, blood vessels, and kidneys detect the increases and stimulate the kidneys to increase sodium excretion, thus returning blood volume to normal. When blood volume or sodium concentration becomes too low, the sensors trigger mechanisms to increase blood volume. These mechanisms include the following: The kidneys stimulate the Overview of the Adrenal Glands to secrete the hormone aldosterone. Aldosterone causes the kidneys to retain sodium and to excrete potassium. When sodium is retained, less urine is produced, eventually causing blood volume to increase. The pituitary gland secretesvasopressin(sometimes called antidiuretic hormone).Vasopressincauses the kidneys to conserve water. 