Know your heart!

I am sure; all of us had an orientation of how our heart is and how it functions in our biology classes in school. As we grew a bit older, the heart was all about love and valentines! And as one grows above that, heart is always spoken of in the context of an attack! So let us spend some time here to know how the engine of your body is designed.

Pure and Impure!

In school, we often spoke of pure and impure blood. We wouldn’t call it so here. Pure blood is the one loaded with oxygen and the one which you called impure is actually the blood de-loaded from oxygen. Often, pictorially, the oxygenated blood is shown in red and the de-oxygenated blood is represented in blue.  The heart is specially designed to see that the flow of these two streams is well coordinated.

How is it designed:

For functional reasons, the heart is divided grossly into the left part which deals with the oxygenated blood coming from the lungs and the right part which deals with the de-oxygenated blood coming from the body. Each of these parts is further divided into an upper receiving chamber called the atrium and a lower pumping chamber called the Ventricle. All the inlets and outlets of the chambers are furnished with valves so that that the blood flows in one direction only. You can now see how important it is to have all the walls of the heart intact so as to prevent the undue mixing of the oxygenated and de-oxygenated streams.

The functional pathway:

Thus, the right atrium receives de-oxygenated blood from the rest of the body. It then pours it in the right ventricle which in turn pushes this blood to the lung through the pulmonary artery. As you breathe, the oxygen gets mixed with this blood in the lungs and gets oxygenated, which then goes to the left atrium via the pulmonary veins. The left atrium, on receiving this blood pours it into the left ventricle which is a strong pump. This left ventricle then pumps this freshly oxygenated blood to the entire body.

The Conduction System:

In order that this receiving and pumping of the heart is carried out in a well coordinated manner, the heart is wired with a very intelligent conduction system. This conduction system sees that the chambers of the heart beat in precise succession, so that there is no mixing and turbulence of the streams. The wiring begins with an impulse generator called the SA node which is situated in the right atrium. It sends impulses to both the atria which then converge at a gate junction between the atria and ventricles which is called the AV node. This AV node delays the impulse a bit so that the ventricles are activated after an adequate filling time. The conduction system them bifurcates into the left and right bundles to supply the corresponding ventricles.

The Engine needs to be oiled as well!

As the heart pumps, it works like an engine. It also needs to be supplied with a good supply of blood. This is achieved through the blood vessels called coronaries. The right coronary artery, the left coronary artery and the circumflex artery are the main channels through which heart is supplied.

Thus we can see that the heart functions just like a power factory and each department of this factory needs to function well to see that ultimately the body is kept alive.

When something goes wrong:

When something goes wrong with the heart, it could be in either of these departments.

1. When the walls separating the oxygenated and de oxygenated blood are not intact, it is called a septal defect. It leads to mixing of the streams and malfunction. Such defects are usually from birth and are detected in the first few years of life. These need to be diagnosed in a timely manner and surgically corrected. Else the life span reduces significantly.
2. When the Valves separating the chambers of the heart become leaky or tight, the flow dynamics of the blood is affected and the body starts suffering. These are the valvular heart diseases. These require management with medicines and eventually surgical replacement with artificial valves.
3. When the conduction system of the heart starts malfunctioning, it immediately affects the coordinated pumping of the heart. This can be like a short circuit or a fuse burn out. This results in either fast heart rate or drastically low heart rates. Some of these conduction defects are life threatening. A special branch in cardiology called electrophysiology deals with these challenges. Highly advanced gadgets are available to diagnose and treat these conduction defects.
4. When the coronary arteries supplying the heart get blocked, it leads to the ischemic heart disease and is discussed in details in the other relevant sections.
5. Finally, when the heart muscle is affected due to a number of reasons, it is called a cardiomyopathy. This requires chiefly monitored medical management and at terminal stages a heart transplant if feasible.

Undoubtedly, the heart is the powerhouse of the body.