Deoxygenated blood inters the right atrium through the inferior and superior vena cavas. The right side of the heart then pumps this deoxygenated blood into the pulmonary veins around the lungs. There, fresh oxygen enters the blood stream, and the blood moves to the left side of the heart, where it is then pumped to the rest of the body
As deoxygenated blood flows into the right atrium, it passes through the tricuspid valve and into the right ventricle, which pumps the blood up through the pulmonary valve and through the pulmonary artery and to the lungs.
Tricuspid valve:Impids blood to go backawards, separates the right atrium and the right ventricle.
1 b.Heart attack: