Define chemical buffer system and describe specifically how the body's four chemical buffer systems help maintain homeostasis

Question

What will be an ideal response?

Answer 1

A chemical buffer consists of a pair of substances involved in a reversible reaction->one substance can yield free H+ to counteract a rise in pH, and another can bind (remove from solution) H+ to counteract a drop in pH. (1) In the carbonic acid-bicarbonate buffering system, CO2 binds with H2O to form carbonic acid (H2CO3), which dissociates to form H+ and HCO3- (bicarbonate). When pH falls, more H2CO3 dissociates to yield H+. When pH rises more HCO3- binds with H+, thus removing them from the solution. (2) The protein buffer system involves the buffering capacity of proteins. When pH is too low, one part of a protein functions as a base and binds with excess H+. When pH is too high, another part of the protein can function as an acid and donate H+ to the solution. (3) In the hemoglobin (Hb) buffering system, Hb in red blood cells picks up H+ formed in the tissues due to CO2 production and the formation of carbonic acid. In the lungs, Hb releases the H+, which binds with HCO3- to form H2CO3 and then CO2 and water; the CO2 is exhaled. (4) The phosphate buffering system consists of an acid phosphate salt (NaH2PO4) that can donate a H+ when the pH rises and a basic phosphate salt (Na2HPO4) that can accept H+ when the pH falls.