PATHOLOGY

Detailed explanation-1: -After the blood gets oxygen in the lungs, it is called oxygen-rich blood. 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.

Detailed explanation-2: -The heart has a total of four chambers: right atrium, right ventricle, left atrium and left ventricle. The right side of the heart collects oxygen-depleted blood and pumps it to the lungs, through the pulmonary arteries, so that the lungs can refresh the blood with a fresh supply of oxygen.