The action of a single heart beat

When was your last anatomy lesson? Click here.

Here is a terrific video animation of the cardiac cycle (which I came across this week at Meddy Bear's Facebook page). Simple and easy to understand, it shows the sequence of events in a single heart beat:

The Cardiac Cycle

The video very clearly shows the major blood vessels (both arteries and veins) that shunt blood into or out of the heart chambers (i.e., the two atria and two ventricles).

Notice how important the heart valves are within the process. These include the tricuspid valve, pulmonary valve, mitral valve, and aortic valve. Their proper opening and closure during the heart's relaxation and contraction phases prevents blood flowing the wrong way back into the heart chambers. In short, the heart valves play a very important role in the effective filling and emptying of the heart chambers during each and every heart beat.

The heart is a pretty important organ. Try to keep yours finely tuned, it has a lot of reps to get through in a day!