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.
Fluid and Electrolyte Balance. The kidneys are essential for regulating the volume and composition of bodily fluids. This page outlines key regulatory systems involving the kidneys for controlling volume, sodium and potassium concentrations, and the pH of bodily fluids.