Sodium in Human Body
Sodium is capable of permeating the cell membrane and muscle contraction and nerve transmission involve a temporary exchange of extracellular sodium and intracellular potassium.
The subsequent transfer of sodium out of the cell is by means of an active mechanism or pump.
A very small amount of sodium occurs intracellularly.
In bone sodium is bound for the most part on the surface of bone crystals. The amount present in bone is by no means small and accounts for 30 to 45 percent of total body sodium.
This reservoir apparently is part of the active labile sodium pool in the body.
Sodium metabolism is regulated primarily by aldosterone, a hormone of the adrenal cortex that promotes the reabsorption of sodium from the kidney tubules.
If the absence of this hormone, sodium excretion is increased and symptoms of deficiency ensue.
Other adrenalin minerolocorticoids, deoxycorticosterone and hydrocortisone, are involved in regulation of sodium excretion but are less potent in action.
Sodium in Human Body
