Define Functions of sodium and chloride?

So far you have learnt that most minerals participate in important functions of body as they support the activity of specific enzymes. In striking contrast to these, Nat and K+ mostly function by changing their location i.e. by passing from one side of the plasma membrane to other. These electrolytes are involved in number of functions as enumerated herewith.

• These electrolytes are required for maintenance of total body water and water .balance. They are major determinants of osmotic pressure and electrolyte balance.
• They are involved in the maintenance of acid-base balance.
• They are major determinants of membrane potential. As you know that sodium is present in higher concentration outside the cell while K within the cell. This intracellular/extracellular difference in their concentration is responsible for the electrical potential gradient across membranes of all cells with nerve and muscle cells having highest gradients. This is critical in signal transmission across the nerve cells, muscle contraction and relaxation, synaptic transmission.
• They are required for the transport of glucose, amino acids within enterocyte.

The plasma membrane enzyme Na⁺/K⁺- ATPase is important for many functions such as water balance, membrane potentials and transport of nutrients. In addition to the above functions, potassium is required for normal growth. Early experiments in intact cells have demonstrated a linear relation between intracellular potassium concentration and cell growth and incorporation of amino acids into protein. Sodium is involved in the formation of mineral apatite of bone while chloride is a constituent of gastric juice.