The red, oxygen carrying pigment in the RBCs of vertebrates is haemoglobin. It consists of the protein globin (polypeptide) united with the pigment haem (heme).
Function of haemoglobin
1. Facilitates transport of oxygen from lungs to the tissues. 2. Facilitates transport of CO2 from the tissues to the lungs. 3. It acts as an excellent acid-base buffer, being a protein. It is responsible for 70% buffering power of whole blood. 4 It plays a role in regulation of blood flow and BP Haemoglobin has additional nitric oxide (NO) binding site on the B-chain which 1S increased by O2. Therefore, haemoglobin binds with NO in the lungs and releases it in the tissues where it promotes vasodilation.
