A pigmented protein (or metelloprotein) that contains iron in the form of heme located in red blood cells of vertebrates and responsible for the delivery of oxygen (about 98% of the total) to tissues (heme being the deep red, non-protein, ferrous component of hemoglobin). The color of blood, which varies from bright red when oxygenated to dark red when it is deoxygenated,is due to hemoglobin.
See Anemia, Blood Oxygenation Level Dependent Contrast (BOLD signal), Carboxyhemoglobin (CoHb), Deoxyhemoglobin (dHB), Functional near-infrared spectroscopy (NIRS), Myoglobin, Optical imaging, Oxyhemoglobin