human heart cross section

anatomy aorta aortic arch ardiac arrest arterial artery atrial atrium attack bag beat being blood body cardia cardiac cardio cardiology cava cavity chart contraction cor coronary cross crosssection cycle diagram diastole electrocardiogram graph heart heartbeat human illustration instructive internal main medical medicine node organ pacemaker parts picture pressure profile pulmonary pump pumps rate section septum sinus structure surgery systole valve vein vena ventricle vessel vessels