What is the Heart?
The heart is indeed a biological miracle. Fist-sized, it pumps blood through the entire body for a whole life time, day and night. It is the blood which supplies nutrients and oxygen to the body. It is through the blood again, that waste products and carbon-dioxide are removed from it. Ironically, we hardly notice the good work of our heart, until it is sick. And when it is sick it could be too late.
Made of a special type of muscle, the heart has the remarkable capacity of beating on its own. While other muscles depend on the brain for movements, the heart has its own electrical impulse generator, which makes the heart beat about 60-80 times a minute at regular intervals. Irregular beats, fast or slow beats are called arrhythmia and require treatment.
How do you get a heart attack?
Although so much blood flows through the heart it gets no nourishment on its own. The heart has to depend on the coronary arteries for blood to keep itself fit. Having to work so hard, the heart demands and gets one of the richest blood supplies in the body. A narrowing of the coronary blood vessels causes ‘Angina’, while a complete blockage of the coronary blood vessels causes ‘Heart Attack’.
What are the chambers of the heart?
The heart has four chambers, two atria (atrium-chamber) and two ventricles (cavities). There is an atrium and a ventricle on the right and one each, on the left side.
Heart Failure results if the ventricles are overworked, overstrained and swollen.
The heart can be compared to a four room apartment or a house.
An apartment has doors between rooms, so does the heart have valves. Just like doors, the valves open in a certain direction when blood flows through them. If the heart valves open in the reverse direction and blood flows in a reverse direction, it is a sign of heart disease.
In an apartment we may freely move to any room, but the blood in our heart can move only in a predefined direction,
between predefined chambers. If the blood flows into the wrong direction and in the wrong chambers, that could be a sign of heart disease too .
Lastly, the rooms in an apartment have walls. The chambers of our heart also have walls. Rarely, these walls may have openings or a weakness in them, another sign of heart disease.
How does the blood flow in the heart ?
The atria receive blood from all the parts of the body and the lungs and push it into the ventricles.
The ventricles contract and push blood through the huge Aorta and Pulmonary Artery and then through the whole body and the lungs respectively.
In this way, the heart keeps the blood flowing through the body, constantly.
If for any reason the ventricles are overloaded, gradually the heart will become weak.
Ventricles push the blood and make it flow, but equally important are the heart valves, which allow blood flow in only the desired direction.
There are four heart valves. The mitral valve is the biggest, and lies between the left atrium and the left ventricle. The tricuspid valve regulates the blood flow between the right atrium and the right ventricle.
The blood always flows from the atria to the ventricles. If it flows in the reverse direction, from ventricles to the atria it is a sign of a major heart disease.
The other two valves in the heart are at the root of the aorta (aortic valve) and at the root of the pulmonary artery (the pulmonary valve)
If any one or more of these four valves are diseased, the heart will not function well and its efficiency will decrease.
Blood comes back to the heart via the veins. The small veins join together to form larger veins, which in turn join to form the two largest veins, the Superior (higher) Vena Cava and the Inferior (lower) Vena Cava. The blood returns to the heart via these huge veins. This blood is poor in oxygen. The right atrium accepts this blood and sends it to the right ventricle, which sends it to the lungs for oxygenation (saturation of blood with oxygen).
Passage through the lungs enriches the oxygen levels in blood.
This oxygenated blood comes to the left atrium, goes to the left ventricle via the mitral valve, and is pushed into the large aorta by the powerful contractions of the left ventricle.
The walls between the two atria and the two ventricles separate the oxygen-rich blood from the oxygen-poor blood.
Any defects or holes in the walls lead to mixing of blood and causes illness. Such defects are usually present from birth and need correction by surgery or nonsurgical interventional treatment.
King or Queen Comparission
In a way the heart is like a benevolent monarch. All its life, the sincere organ gives life blood to all the other organs of the body. If it stops, its dependant organs will suffer and eventually die.
But what about blood supply to the emperor himself? It too needs blood, which it has to get from the coronary arteries. When these coronary arteries are narrowed and the heart gets inadequate blood, it is a serious disease process, called Coronary Artery Disease (CAD). Narrowed coronaries trigger chest pain, called ‘Angina’. When the coronary arteries are completely blocked, it is a life-threatening situation, and is called a ‘Heart Attack’.