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What are the three major buffer systems of the body and how do they work?

1 Answer
Sep 24, 2016


The three major buffer systems of our body are carbonic acid bicarbonate buffer system, phosphate buffer system and protein buffer system.


The body's chemical buffer system consists of three individual buffers out of which the carbonic acid bicarbonate buffer is the most important.

Cellular respiration produces carbon dioxide as a waste product. This is immediately converted to bicarbonate ion in the blood. On reaching the lungs it is again converted to and released as carbon dioxide.
While in the blood , it neutralises acids released due to other metabolic processes. In the stomach and deudenum it also neutralises gastric acids and stabilises the intra cellular pH of epithelial cells by the secretions of bicarbonate ions into the gastric mucosa.

Phosphate buffer system operates in the internal fluids of all cells. It consists of dihydrogen phosphate ions as the hydrogen ion donor ( acid ) and hydrogen phosphate ion as the ion acceptor ( base ) . If additional hydroxide ions enter the cellular fluid, they are neutralised by the dihydrogen phosphate ion. If extra hydrogen ions enter the cellular fluid then they are neutralised by the hydrogen phosphate ion.

Protein buffer system helps to maintain acidity in and around the cells. Haemoglobin makes an excellent buffer by binding to small amounts of acids in the blood, before they can alter the pH of the blood. Other proteins containing amino acid histidine are also good at buffering.

The main purpose of all these buffers is to maintain proper pH within the body system so that all biochemical process can take place.