The Bohr effect states that in the setting of increased CO2 and H+ (i.e. at metabolically active tissues) O2 will increase unloading to tissues (right-ward shift in the O2-Hgb dissociation curve)

Once O2 is unloaded at the tissues, the Haldane effect can be seen. The Haldane effect states that in the presence of low O2 concentrations, CO2 binds more strongly to hemoglobin. This allows CO2 to be carried away from the tissues.

Conversely, the Haldane effect also demonstrates that in the presence of increased O2 concentrations, hemoglobin's affinity for CO2 decreases. This allows for the unloading and elimination of CO2 in the lungs.

The Bohr effect then comes into play again in the lungs where the relatively low concentrations of CO2 and H+ in the lungs allow for hemoglobin to have increased affinity for O2, picking up O2 in the lungs.

a) Decreased O2-Hgb dissociation
b) Increased O2-Hgb dissociation
c) Decreased CO2-Hgb binding
d) Increased CO2-Hgb binding