500
TRACE A DROP OF BLOOD TROUGH THE HUMAN HEART, STARING WITH INFERIOR & SUPERIOR VENA CAVA: (INCLUDE VALVES)
RIGHT ATRIUM, TRICUSPID VALVE, RIGHT VENTRICLE, PULMONIC VALVE, PULMONARY ARTERY, LUNGS, PULMONARY VEIN, LEFT ATRIUM, MTRAL VALVE (OE BICUSPID) LEFT VENTRICLE, AORTIC VALVE, AORTA, OUT TO THE BODY