Labels:daily | web site OCR: ATRIUM OUR LEFT AND RIGHT ATRIA (one IS an atrium are the two upper chambers of your heart. They are smaller than the two lower cham bers or ventricles, and have thinner walls. Your atria receive blood returning to your heart from vour circulation Oxygen- rich blood from your lungs enters the left atrium through four pulmonary veins. Oxygen- -poor blood from your body enters the right atrium through two large veins called the superior vena cava and the inferior vena cava Blood is squeezed from the atria to the ventric TRIUM
