Cardiac Conduction System

When you listen to your heart beat, you never stop to wonder why it beats, how does it beat and what causes it to beat. Do you ever ponder why it never stops beating however much you want it to. Why cant you control it like you control your muscles or the way you breathe, or may be open and close your eyes as you please. There are muscle in our bodies which are controlled by the parasympathetic and sympathetic nervous systems. The way you can move from one place to another and come back, when you choose to lift your book-pack and when you dont feel like it. All these movements you choose to do are controlled by you. but beyond what we can control, lies the uncontrollable. The muscles of the heart are not close to being control by you. Lets just say they have thier own world and a small brain that tells them what to do and not you. think this is your heart and it's in yo body but you dont have control over it. You dont tell it when to start and when to stop beating.

All these questions can be understood by simple understand the functions of these structures that make the heart beat. First, the heart is composed of muscle which are capable of initiating there own electric impulse.

The process by which this happens is called the Cardiac Conduction system. The Cardiac Conduction System generates lightning-fast electrical impulses which are rapidly conducted through the heart muscle. This impulse causes the heart chambers to contract in a rhythmic sequence, pumping blood throughout the body.
The elements comprising the Cardiac Conduction system are the sinoatrial node (also referred to as the "SA node" or "pacemaker"), the atrioventricular node ("AV node") and certain fibers of the autonomic nervous system atrioventricular bundle also referred to as the Bundle of His, right and left bundles branches and the purkinje fibers.
The sinoatrial node is a small lump of neural tissue located in the right atrium of the heart. This tiny cluster of cells is responsible for initiating the electrical impulse that causes the heart to beat. This impulse travels rapidly throughout the cells of the atria causing them to contract then continues on to the AV node.

Located near the center of the heart, the AV node serves as a kind of "gatekeeper" delaying the electrical impulse before relaying it on to stimulate the ventricles. This slight delay ensures that the right and left atria have had sufficient time to contract before the ventricles do. From here, the impulse travels on to the right and left ventricles by way of the bundle of His. These specialized autonomic nerve fibers are located inside the muscular walls of the heart. The impulse is passed through the muscle cells of the ventricles causing them to contract and forcefully eject the blood contained within.Once complete, the cycle begins again to keep your heart beating... and your blood flowing.

The understanding of how the heart works, generates its own impulse and capable of changing the rate at which it beats, has become a big contribution to the improvement of patients with heart failures. Scientists have introduced artificial pacemakers which is connected directly to the chambers of the heart. Pacemakers are designed to meet specefic needs which may include increasing or decreasing the pulse rate to match the activities for example running, walking, resting, while other boost the impulse of the heart when needed.

With this complex gift, that our bodies possesses, we should be able to thank whoever made the heart.

Posted by M. Lubega