Labels:daily OCR: HEART OUR HEART is fist- -sized. muscular bag W eighing about 450 g (1 lb), W hich pumps blood around your body Its walls are made of cardiac muscle which contracts about 70 times per minute Your heart is actually two pumps joined together. Each one has an upper cham ber, or atrium. into which blood enters. Blood then passes on to a lower thick- walled cham ber or ventricle, which pumps blood out of the heart. The pump on the right side pushes blood to your lungs. It then returns to the pump on the left which pushes around your body return
