The lower boundary of the exosphere is called the exobase. It is also called exopause and 'critical altitude' as this is the altitude where barometric conditions no longer apply. Atmospheric temperature becomes nearly a constant above this altitude.
Sodium â the volatility and solvent mineral: essential to life, all body fluids contain sodium â itâs needed for many biochemical processes including water balance regulation, fluid distribution on either side of the cell walls, muscle contraction and expansion, nerve stimulation and acid-alkaline balance.
Summary. 1  Sodium and chloride â major electrolytes of the fluid compartment outside of cells (i.e., extracellular) â work together to control extracellular volume and blood pressure. Disturbances in sodium concentrations in the extracellular fluid are associated with disorders of water balance.