Copyright o The MoGraw-Hill Companies, Ine. Permission required for reproduction or display. The heart is the pump that propels ds the blood through Puimonary truna Pulmonary arents the systemic and pulmonary cIrcuits. Red color indicates blood that is fully oxygenated Blue color represents blood that is only partially oxygenated exon the ungsThe heart is the pump that propels the blood through the systemic and pulmonary circuits. Red color indicates blood that is fully oxygenated. Blue color represents blood that is only partially oxygenated