Extracellular fluid volume and electrolyte homeostasis

Extracellular fluid volume and electrolyte homeostasis refers to the tightly regulated processes in the human body that maintain the volume of extracellular fluid and the balance of dissolved electrolytes, primarily sodium, potassium, calcium, and chloride. These processes depend on hormones such as vasopressin (antidiuretic hormone), aldosterone, and systems like the renin-angiotensin-aldosterone system (RAAS), as well as neural mechanisms that sense changes in plasma volume and composition. Sodium is the major cation determining ECF volume, while osmoreceptors in the hypothalamus and volume receptors in the cardiovascular system control thirst and renal excretion to adjust fluid balance. These adaptations safeguard homeostasis necessary for normal cellular, cardiovascular, and neurological function, and disruptions can result in life-threatening conditions such as shock, edema, or electrolyte disturbances.

Other names

Fluid and electrolyte balanceBody fluid regulationECF volume regulationElectrolyte homeostasis

Inhibition or modulation of renal sodium reabsorption. Alteration of hormone activity regulating water/sodium retention (RAAS, ADH). Adjustment of diuresis, natriuresis, and blood volume. Direct or indirect modulation of thirst reflex and osmoreceptors.