Blood entering the right atrium and right ventricle, that is, venous blood, is approximately 75% saturated. Following passage through the pulmonary circuit where oxygen is taken up by erythrocytes containing hemoglobin, the blood becomes 95-98% saturated - it is now "arterialized". Oxygen saturation remains as such in the left atrium, left ventricle, and aorta. Small differences in saturation between the pulmonary capillary and aortic blood are due to shunting, involving some admixture of less saturated blood in the lung.
Animated cardiac cycle cartoons are also available.
Go to Next Page
Return to Previous Page
Return to Index