natriumbalanse

Natriumbalance refers to the regulation of the body's total sodium content, ensuring that sodium intake is matched by excretion to maintain extracellular fluid volume and plasma osmolality. Sodium is the principal extracellular cation and influences blood volume, nerve function, and muscle contraction. The kidneys are the primary regulators, eliminating or reabsorbing sodium along the nephron in response to hormonal cues.

Key regulatory systems include the renin–angiotensin–aldosterone system (RAAS), which increases sodium reabsorption in the distal nephron when perfusion or blood pressure falls; aldosterone stimulates sodium reabsorption in the collecting ducts. Atrial natriuretic peptide (ANP) promotes natriuresis and diuresis when atrial stretch is high, helping reduce blood volume. Antidiuretic hormone (ADH, vasopressin) mainly controls water reabsorption and thereby indirectly affects sodium concentration through changes in osmolality. The gut absorbs sodium, and small amounts are lost through sweat and skin.

Disturbances of natriumbalance can lead to hyponatremia or hypernatremia. Hyponatremia often results from excess free water relative to sodium (such as in SIADH or fluid overload) or salt wasting; hypernatremia from water loss or inadequate intake. Medications like diuretics modify natriuresis and electrolyte balance and can impact blood pressure. Assessment typically includes plasma sodium concentration, urinary sodium, and evaluation of volume status.

Maintaining natriumbalance is essential for stable blood pressure and overall fluid homeostasis. Diet, hydration, renal function, and endocrine regulation all contribute to this balance.