The pulmonary valve is one of the four main valves in the heart. It is located between the right ventricle and the pulmonary artery. Its primary function is to prevent blood from flowing back into the heart after it has been pumped out to the lungs for oxygenation. When the right ventricle contracts, the pulmonary valve opens, allowing deoxygenated blood to flow into the pulmonary artery. Once the blood is in the lungs, the valve closes to ensure that blood does not return to the heart. This process is essential for maintaining proper blood circulation and oxygen levels in the body.