Video narration
How can one heart send blood to both your lungs and the rest of your body? Like a squeeze bottle, the heart pushes blood forward; valves help prevent backflow. Blood returning from your body enters the right atrium, an upper chamber, then the right ventricle, a lower pumping chamber. It travels through an artery to your lungs, where it picks up oxygen. From the lungs, oxygen-rich blood returns to the left atrium, an upper chamber, then the left ventricle, a lower pumping chamber. The left ventricle pushes it through the aorta, the main artery, around your body, delivering oxygen. A wall separates the sides, and valves keep blood moving forward. The heart is not one pump doing one job: its right side sends blood to the lungs, while its left sends it around your body. One heart serves both through two coordinated pumps.