Blood gas tension constant 0.0031 represents the amount of oxygen dissolved in plasma. The dissolved-oxygen term is generally small relative to the term for hemoglobin-bound oxygen, but becomes significant at very high PO (as in a hyperbaric chamber) or in severe anemia. This is an estimation and does not account for differences in temperature, pH and concentrations of 2,3 DPG. Blood gas tension Blood gas tension refers to the partial pressure of gases in blood. There are several significant purposes for measuring gas tension; the most common gas tensions measured are oxygen tension (PO), the carbon dioxide tension (PCO) and carbon monoxide tension
Hemoglobin of the amount of oxygen in a patient's blood by an instrument called a pulse oximeter. This difference also accounts for the presentation of cyanosis, the blue to purplish color that tissues develop during hypoxia. Deoxygenated hemoglobin is paramagnetic; it is weakly attracted to magnetic fields. In contrast, oxygenated hemoglobin exhibits diamagnetism, a weak repulsion from a magnetic field. Scientists agree that the event that separated myoglobin from hemoglobin occurred after lampreys diverged from jawed vertebrates. This separation of myoglobin and hemoglobin allowed for the different functions of the two molecules to arise and develop: myoglobin has more to do