Describe the blood flow through the heart

Venous blood enters the heart through the vena cava, it drains into the right atrium. The blood then flows through the tricuspid valve into the right ventricle. When the heart contracts the blood is ejected through the pulmonary valve into the pulmonary artery and flows towards the lungs.

In the lungs the blood is then oxygenated and flows back into the left atrium via the pulmonary veins. From the left atrium the blood then flows through the mitral valve into the left ventricle. The left ventricle then contracts and pushes blood into the aorta, from where it is transported to the rest of the body.