Describe how deoxygenated blood flows through the heart

Deoxygenated blood from the body flows into the right atrium via the vena cava. The right atrium contracts, forcing open the tricuspid valve. This allows blood to flow from the right atrium into the right ventricle. The right ventricle contracts which causes the tricuspid valve to close. Soon after, the semilunar valves in the pulmonary artery open allowing blood to flow from the right ventricle into the pulmonary artery. Blood flows via this artery to the lungs to be oxygenated.