Normal Heart Anatomy and Blood Flow

The heart has four chambers.  The two upper filling chambers (the left and right atria) and two lower pumping chambers (the left and right ventricles.  Blue blood returning from the body drains from two large veins (the inferior and superior vena cava) into the right arium.  F From there blood enters the right ventricle where it is pumped out through the pulmonary arteries to the lungs.  In the lungs, blue blood turns into red blood as it carries oxygen back to the heart, returning to the left atrium.  Finally, oxygen enriched red blood enters the left ventricle and is pumped into the aorta where it is distributed to the rest of the body.