Hello

The heart function in a following ways :

The arteries receive oxygenated blood from heart and it supply it throughout the body . Whereas th veins carry the deoxygenated blood from all the part of our body to the heart for oxygenation.

The right atrium received blood from the veins and pump it to the right ventricle .

The right ventricle pump the blood to the lungs .

The left atrium received the oxygenated blood from the lungs and pump it to the left ventricle .

The left ventricle pumps the blood throughout the human body.

Good Luck