肺静脉血的氧气饱和程度还达到75%。
去氧血红蛋白的颜色是紫蓝色的，这应该是完全不含氧的血液的颜色。
hemoglobin
Protein in the blood of many animals (in vertebrates it is in red blood cells) that transports oxygen from the lungs to the tissues. It is bright red when combined with oxygen and purple-blue in the deoxygenated state. Each molecule is made up of a globin (a type of protein) and four heme groups. Heme, a complex heterocyclic compound, is an organic molecule derived from porphyrin with an iron atom at the centre. Variant hemoglobins (see sickle-cell anemia; hemoglobinopathy) can be used to trace past human migrations and to study genetic relationships among populations.
For more information on hemoglobin, visit Britannica.com. Britannica Concise Encyclopedia