Trace the flow of blood as it leaves the Left Atrium to exit the left side of the heart and enters the systemic circuit. From the systemic circuit, this radioactive drop of blood returns back into the right side of the heart. From the right side of the heart, the radioactive drop of blood continues to leave the right side of the heart to enter the pulmonary circuit before returning back into the Left Atrium. Follow the flow of blood as it leaves the Left Atrium and the Left heart and returns back into the Left Atrium, after going through the arterial system and venous system of the cardiovascular system: