Roar (song) is a song by Katy Perry.
A heart valve normally allows blood to flow in only one direction through the heart .. blood. blood. heart. heart. The four valves commonly represented in a mammalian heart determine the pathway of blood flow through the heart .. blood. blood. heart. heart. blood flow. blood flow. A heart valve opens or closes incumbent on differential blood pressure on each side .. blood. blood. heart. heart. blood pressure. blood pressure. The four main valves in the heart are  :. heart. heart. The two atrioventricular -LRB- AV -RRB- valves , the mitral valve -LRB- bicuspid valve -RRB- , and the tricuspid valve , which are between the upper chambers -LRB- atria -RRB- and the lower chambers -LRB- ventricles -RRB- .. mitral valve. mitral valve. tricuspid valve. tricuspid valve. The two semilunar -LRB- SL -RRB- valves , the aortic valve and the pulmonary valve , which are in the arteries leaving the heart .. heart. heart. aortic valve. aortic valve. pulmonary valve. pulmonary valve. The mitral valve and the aortic valve are in the left heart ; the tricuspid valve and the pulmonary valve are in the right heart .. heart. heart. mitral valve. mitral valve. tricuspid valve. tricuspid valve. aortic valve. aortic valve. pulmonary valve. pulmonary valve. There are also the coronary sinus and the inferior vena cava valves .. coronary sinus. valve of the coronary sinus. inferior vena cava valves. valve of the inferior vena cava