The human heart is a four chambered heart. It has two ventricles and two auricles connected through valves. The tricuspid valve present at the junction of the right auricle and right ventricle, whereas the bicuspid valve is present at the junction of left auricle and left ventricle. The four chambered heart helps to purify blood and segregate oxygenated and deoxygenated blood so that the body receives blood in its purest form. It also makes the heart work more efficiently.

· Deoxygenated blood is brought to the heart by vena cava

· It is received by the right auricle of the heart

· Once collected, the right auricle contracts and the blood moves from the right auricle to the right ventricle through the tricuspid valve

· The ventricle contracts and the blood moves to the lungs through the pulmonary artery (the only artery in the human body carrying deoxygenated blood). Its entry is guarded by the semilunar valves

· On reaching the lungs, the blood gets purified, i.e., becomes oxygenated and it moved back to the heart through pulmonary veins (the only vein that carries oxygenated blood)

· The blood enters the left auricle of the heart and then moves to the left ventricle. This junction is guarded by the bicuspid valves

· The left ventricle contracts and the oxygenated blood moves through the aorta outside the heart

· The muscles of the left ventricle is the strongest as it has to pump the blood to aorta which in turn pumps blood through out the body

· The opening of aorta is guarded by aortic valve.

This was the most simplest mechanism of how blood gets purified and pumped throughout the body. However, the mechanism involves much more complex elements of the cardiac cycle.

Thus, this was a summary of how four chambered heart helps in the transport of pure oxygenated blood.

Some organisms
lack a four chambered heart. They have a 3 chambered heart which transports
mixed blood, i.e., a mixture of oxygenated and deoxygenated blood throughout
the body. Similarly, most lower organisms have a two chambered heart that transports
only deoxygenated blood.

I hope this answer helps.