PATHOLOGY

Detailed explanation-1: -Oxygen-rich blood flows from the lungs back into the left atrium (LA), or the left upper chamber of the heart, through four pulmonary veins. Oxygen-rich blood then flows through the mitral valve (MV) into the left ventricle (LV), or the left lower chamber.

Detailed explanation-2: -From the heart the blood is pumped back to the lungs where the carbon dioxide is released from the blood into the air sacs to be breathed out. Air is breathed in, oxygen is picked up by the blood and the journey begins again. All the systems in our body rely on oxygen to make energy.

Detailed explanation-3: -Blood enters the right atrium and passes through the right ventricle. The right ventricle pumps the blood to the lungs where it becomes oxygenated. The oxygenated blood is brought back to the heart by the pulmonary veins which enter the left atrium. From the left atrium blood flows into the left ventricle.