Re: the 3 types of Blood Buffers

Hi Evan
 pH levels in biological systems is very important, as you might have 
discussed in your chemistry class.  To keep our blood at about pH 7.4 our 
body uses three different types of buffers.  pH is controlled by the 
concentration of hydrogen atoms - H+ - in a solution.  Buffers work to 
lower pH (make your blood more acidic if the level is above 7.4) by 
releasing hydrogen atoms into your blood.  The reverse happens if your 
blood is too acidic; hydrogen atoms are taken up by the buffers, 
decreasing the H+ concentration and increasing pH.  
 There are three classes of blood buffers.  The first two you already know 
about.  These are phosphate buffers which change between [H2PO4](-1) and 
[HPO4](-2).  While used in the blood buffer system, phosphate buffers are 
very important in the urinary buffer system.  The 2nd type are the 
bicarbonate buffers.  These change between [HCO3](-1) and [H2CO3].  Now, 
to answer your question.  The 3rd type of buffers are protein buffers.  
These are probably the most important out of the three types found in the 
blood system.  They include proteins such as hemoglobin (the protein that 
carries oxygen through your blood).  Buffer proteins contain basic and 
acidic groups that may either act as hydrogen ion acceptors or donors to 
help maintain blood pH. 
 I hope that answers your question for you.  

~Ashley Calder

PS:  I found most of this information by typing "blood buffers" into a 
search engine...  this is the website I used: 
pH of the Blood: Acid-Base Balance 

PPS: The numbers in brackets after the bicarbonate/phosphate formulae are 
to indicate the overall charge of the whole molecule.