From Body Veins to Heart | Vena Cava Flow 💙🫀 - - In this 3D beating heart, you’re watching venous blood return from the whole body into the right atrium. The blue stream shows deoxygenated blood coming from the superior vena cava (upper body) and the inferior vena cava (lower body) before it moves through the tricuspid valve toward the lungs. For anyone who is confused by the blue color: this “blue” blood is actually dark red in real life. We simply color it blue here to clearly highlight the