The atria are the upper chambers of the heart that receiveblood.
Oxygenatedblood then returns to the left side of the heart through the pulmonary vein.
Pulmonarycirculation involves deoxygenatedblood flowing from the right ventricle to the lungs via the pulmonary trunk (pulmonary artery) and returning as oxygenatedblood to the left atrium via the four pulmonary veins.
