There's no doubt that the heart is the hardest working organ in the body. This vital muscle is constantly pumping blood throughout the body, from before we're even born to the moment we breathe our last breath. In order for this blood-pumping process to stay in working order, there are a number of different components that must work together in perfect harmony. Here you can find out how exactly your heart works to keep your body alive and moving, day in and day out.