The Heart - Structure.

Blood flows through the:

Vena Cava (superior and inferior) into the Right atrium through the tricuspid valve into the right ventricle through the semi-lunar valve into the Pulmonary artery where the blood is then oxygenated in the lungs. It returns to the heart through the pulmonary vein into the left atrium through the bicuspid valve into the left ventricle through the semi-lunar valve in to the Aorta and then the rest of the body.

Valves prevent back flow, the atrio-ventricular valves and semi-lunar…