Question

Apart from the bicarbonate/blood buffer system, pick one other kind of acid base buffer system and explain its role and function in the human body

Answer 1

Physiological buffers are important players to maintain constant physiological pH despite consumption of foods or liquids which either elevate or decrease body pH. The major buffering system in blood is contributed by acid-base buffer system of bicarbonate/blood. However, there are other body fluids such as urine, intra cellular fluids (ICF) where different Acid-base buffers play a key role to maintain consistent physiological pH , one of the best example is phosphate buffer system which is vital to maintain pH in urine and intracellular fluids majorly but also 5 % of buffering capacity towards blood buffer system.

Phosphate buffer system is made up of dihydrogen phosphate ions (H₂PO₄^-, an acid) and hydrogen phosphate ions (HPO₄², a base). The equilibrium achieved by these two ions maintains pH and is shown below:

H₂PO₄^-(aq) <...........> H⁺(aq) + HPO₄^2-(aq)

Whenever there is an additional presence of hydrogen ions in the cellular fluid then they react with HPO₄^2-, thus produces more dihydrogen phosphate ions (H₂PO₄^{- , while} as if there is more OH^- ions then they react with H₂PO₄^-, resulting in the production of HPO₄^2- . Therefore to maintain cellular fluid pH in the range of 6.9-7.4, phosphate buffer is the major buffering system within the human body.