The element is available in table salt.
A proper balance of sodium and potassium is essential.
Its absorption is under control of aldasterone.
The various functions of sodium are -
(a) It maintains along with chlorine a proper osmotic concentration in the blood for dissolution of blood proteins and turgidity of red blood corpuscles.
(b) It maintains the osmotic concentration of tissue fluid.
(c) Along with potassium, it maintains membrane permeability and membrane potential.
(d) Along with potassium it is essential for conduction of impulses in the nerve cells.
(e) To control heart beat.