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.
From the right ventricle, blood flows through the pulmonary valve to the lungs via the pulmonary arteries (deoxygenated blood). In the lungs the blood becomes more red in color as it is oxygenated. Blood returns to the heart via the pulmonary veins (oxygenated blood) to the left atrium.