Different Valves in Heart & Their Function

The human heart is one of the most complex organs in the body, pumping oxygenated and purified blood to different parts of the body through the circulatory system. Along with oxygen, nutrients are also carried via the blood to the tissues and the muscles. Along with arteries and veins, the heart also comprises of different valves, which play an important role in the proper functioning of the organ. In this article, we will discuss the different valves present in the heart and the functions that they carry out.

(Note: This content is prepared under the guidance of Dr. Zainulabedin Hamdulay – Leading Cardiac Surgeon in Mumbai, India)

What are heart valves?
There are four different chambers in the human heart – two upper chambers and two lower chambers. The upper chambers are known as atria, and the lower chambers are known as ventricles. Before leaving each chamber of the heart, blood has to pass through a valve. One of the main functions of the valves is to prevent the backward flow of the blood into the chambers. If you study the nature of the valves carefully, you will find that they are the kinds of flaps or leaflets which act as a one-way inlet for the blood coming into a ventricle. It also acts as a one-way outlet for blood going out of a ventricle. Normally, all the valves in the heart have three flaps (leaflets), apart from the mitral valve. The mitral valve comprises of only two flaps.

The four valves of the heart
Mentioned below are the four valves of the heart in order of blood circulation and the functions that they do:

•  Tricuspid Valve – The tricuspid valve is located between the right atrium and right ventricle. This valve helps in controlling blood flow from the atria to the ventricles. It helps in closing off the upper right chamber, which is known as the atria, which holds the blood that comes from different parts of the body. The tricuspid valve opens for allowing blood to flow from the top right chamber of the heart to the lower right chamber. Precisely, the blood flow takes place from the right atrium to the right ventricle. The valve also plays an important role in preventing the backflow of blood to the atrium from the ventricle when blood is pumped out of the ventricle.
• Pulmonary Valve (also known as a pulmonic valve) – The pulmonary valve is situated between the right ventricle and the pulmonary artery. This valve helps in controlling blood flow out of the ventricles. The pulmonary valve helps in closing of the lower right chamber, which is also known as the right ventricle. This valve opens for allowing blood to be pumped to the lungs from the heart. This takes place through the pulmonary artery, where the blood receives oxygen.
• Mitral Valve – The mitral valve is located between the left atrium and the left ventricle. The mitral valve helps in controlling blood flow to the ventricles from the atria. This valve closes off the upper left chamber, also known as the left atrium, and also helps in collecting oxygen-rich blood coming in from the lungs. The mitral valve also opens for allowing blood to pass to the lower left side from the upper left side. This means that the valve allows blood to pass from the left atrium to the left ventricle.
• Aortic Valve – This particular valve is located between the left ventricle and the aorta. The aortic valve helps in controlling blood flow out of the ventricles. The aortic valve helps in closing of the lower left chamber, which helps in holding the oxygen-rich blood before the blood is pumped out to the body. The aortic valve also opens for allowing blood to leave the heart. The blood goes from the left ventricle to the aorta and then on to the body.

How do the various valves in the heart function?
The blood flow is regulated in the heart and then to the body by the functioning of the heart valves. The valves those present in the heart open and shut as the heart muscles contract and relax. In this process, the blood flows into the ventricles and the atria at other times. The step by step functioning of the valves is as follows.

When the left side ventricle contracts, the aortic valve closes, and the mitral valve opens. This allows blood flow into the left ventricle from the left atrium.

Now, as the left atrium contracts, more amount of blood flows into the left ventricle.
When there is a contraction of the left ventricle, the mitral valve closes, and the aortic valve opens. As a result of this, blood flows into the aorta.
Without proper working of the valves, various kinds of problems might take place. The valves should open all the way completely so that the right amount of blood can pass through the valves. Also, the valves should close tightly so that blood does not flow back or leak back into the heart chamber.

Malfunctioning of the heart valves and various kinds of heart valve diseases
Now that we know the importance of heart valves, it is difficult to ignore any kinds of problems which emanate in the valves. However, there are many cases where the heart valves malfunction and need treatment. Some of the most common heart valve diseases are as follows:

• Stenosis – Stenosis is the medical name for narrowing of the valve. People who suffer from stenosis have their valve opening narrowed. As a result, the function of the valve, which has to open does not open properly. And when this happens, the heart is not able to pump blood through the narrow valve. The higher force of the blood is needed for pumping blood through the stenotic valves.
• Regurgitation – This means leakage of the valve. In this valve problem, it does not close properly, and hence, the blood flows in a backward direction into the chamber. Leakage of blood takes place into the atria from the ventricles. Sometimes blood leakage is also seen in the ventricles.
• Atresia – In this problem, the valve opening does not develop at all. Hence, blood does not pass from the atria to ventricle or from ventricle to the aorta or pulmonary artery.

Problems with heart valve should be rectified immediately to prevent further issues.