4th July 2024

Sodium

Sodium is vital in maintaining extracellular fluid volume and membrane potential regulation. Regulation occurs in the kidneys where the majority of reabsorption takes place in the proximal convoluted tubule. Owing to the isotonic nature of reabsorption at this point in the nephron, water is also reabsorbed here. Further sodium reabsorption occurs in the distal ascending portion of the loop of Henle, with only 5%-10% of reabsorption taking place in the distal convoluted tubule and cortical and medullary collecting ducts. Nevertheless, the reabsorption along the distal nephron remains vital and highly regulated.