The depiction of an event late in the game was inspired by Crisis Core: Final Fantasy VII, a storyline tying into the opening of Final Fantasy VII. Ifrit's throne resembles the throne Chaos sits in in a concept art piece by Yoshitaka Amano. for the original Final Fantasy.
The blood first enters the heart into the right atrium. Blood passes from the right atrium through the tricuspid valve and into the right ventricle. When the right ventricle contracts, the muscular force pushes blood through the pulmonary semilunar valve into the pulmonary artery. The blood then travels to the lungs, where it receives oxygen. Next, it drains out of the lungs via the pulmonary veins, and travels to the left atrium.
The pulmonary valve opens to allow blood to flow from the right lower chamber into the pulmonary artery. This artery carries blood to the lungs to get oxygen. At the same time, the aortic valve opens to allow blood to flow from the left lower chamber into the aorta.