Human respiratory system Physiology Human respiratory system Dr. Jagdish Kaur P.G.G.C.,Sector 11 Chandigarh

Haldane effect Describes the effect of oxygen on CO2 transport. Deoxygenated blood can carry increasing amounts of carbon dioxide whereas oxygenated blood has a reduced carbon dioxide capacity. Facilitates the release of O2 at the tissues and the uptake of O2 at the lungs. Deoxygenated hemoglobin has a higher affinity (~3.5 x) for CO2 than does oxyhemoglobin. because it is a better proton acceptor than oxygenated hemoglobin. Therefore, when hemoglobin is deoxygenated (i.e., at tissues) there is a right shift of the carbonic acid-bicarbonate buffer equation to produce H+ which in turn increases the amount of CO2 which can be carried by the blood back to the lungs to be exhaled.

The following is the general equation of the Haldane Effect Then, with oxygenation at the lungs CO2 dissociates more readily from hemoglobin. CO2 + H2O ⇆ H2CO3 ⇆ H+ + H+CO3- The following is the general equation of the Haldane Effect H+ + HbO2 ←→ H+Hb + O2 Haldane effect allows for approximately 50% of the CO2 excreted by the lungs Physiologically much more important than its reciprocal counterpart, the Bohr effect (the effect of carbon dioxide on oxygen transport).

The Bohr effect The effect of carbon dioxide on oxygen transport high CO2 & H+ ion concentration,LOW ph, high temp. -> as O2 is given up in tissues -> CO2 begins to bind & form carbonic acid -> shifts curve to right -> enhancing O2 off loading. blood passing through lungs gives up CO2 & H+ ions in the form of carbonic acid -> shifts O2 dissociation curve to left -> quantity of O2 binding increases at any given PO2 -> increased O2 transport to tissues.