The Heart and Circulatory System
Expert

Blood flows from the extremities towards the inferior vena cava and superior vena cava. Blood enters the right atrium from the inferior vena cava and superior vena cava.
Blood enters the right atrium from the inferior vena cava and superior vena cava. Flow passes from the right atrium through the tricuspid valve to the right ventricle.
Flow passes from the right atrium through the tricuspid valve to the right ventricle. From the right ventricle, blood flows oneway through the pulmonary valve onto the pulmonary artery.
From the right ventricle, blood flows oneway through the pulmonary valve onto the pulmonary artery.
The blood flows through the pulmonary artery to the lungs where it is cleansed and oxygenated. The blood flows through the pulmonary artery to the lungs where it is cleansed and oxygenated.
Blood flows from the lungs back to the heart through the pulmonary veins. Blood flows from the lungs back to the heart through the pulmonary veins. Blood then enters the left atrium from the pulmonary vein.
Blood then enters the left atrium from the pulmonary vein. Flow passes from the left atrium through the mitral valve into the left ventricle.
Flow passes from the left atrium through the mitral valve into the left ventricle. Blood then flows out of the heart through the aortic valve into the aorta.
Blood then flows out of the heart through the aortic valve into the aorta. The blood in the aorta flows to all parts of the body.
The blood in the aorta flows to all parts of the body.

contract and systolic 
contract and systolic  diastolic and relax
diastolic and relax

membranes endocardium and myocardium
membranes endocardium and myocardium epicardium and pericardium
epicardium and pericardium