Heart valves are structures which ensure that blood flows in only one direction. The Heart is divided into four chambers - two upper chambers (Atrioventricular valves) and two lower chambers (Semilunar valves).
- Atrioventricular valves - These include two valves: The Tricuspid valve and the Mitral valve. The tricuspid valve is found between the right ventricle and the right atrium. The Mitral valve is positioned between the left atrium and the left ventricle.
- Semilunar valves- These include- the Pulmonary valve and the Aortic valve. The pulmonary valve is positioned between the right ventricle and the pulmonary artery. The Aortic valve is situated between the left ventricle and the aorta.
The valves open and shut as the heart muscles contract and relax. This process lets the blood flow alternatively in the ventricle and the atria. Let's have a look at the process-
- At the time when the left ventricle relaxes, the aortic valve closes, and the mitral valve opens up. Therefore, the blood flows from the left atrium to the left ventricle.
- When the left atrium contracts, the left ventricle gets even more blow.
- Further when the left ventricle contracts, the mitral valve closes, and the aortic valve opens up. This lets the blood flow into the aorta and to the whole body.
- The right ventricle also relaxes when the left ventricle is relaxing. Due to this, the pulmonary valve closes, plus the tricuspid valve opens. The blood that returned to the right atrium from the body flows into the left ventricle.
- The right ventricle contracts when the left ventricle contracts, causing the pulmonary valve to open and the tricuspid valve to close. Then, the blood flows out of the right ventricle towards the lungs before returning to the left atrium as fresh and oxygenated blood.
Valves are like flaps which act as one-way inlets for blood entering a ventricle and leaving a ventricle. All valves have three flaps except for the Mitral valve. The mitral valve has only two flaps or leaflets.
Aortic Valve vs Mitral Valve
All the valves have an essential role in the proper functioning of the heart, maintaining the blood flow and preventing the backflow of the blood. The key difference between the aortic valve and the mitral valve is that- the Mitral valve is positioned between the left atrium and the left ventricle; the aortic valve is positioned between the left ventricle and the aorta. Another difference is that the Aortic valve has three cusps (flaps), whereas the Mitral valve has only two. The differences between the Aortic valve and the Mitral valve are explained further in detail.
Difference Between Aortic Valve and Mitral Valve in Tabular Form
|Parameters of Comparison||Aortic Valve||Mitral Valve|
|Definition||Aortic valve is a Semilunar valve, consisting of three cups.||Mitral valve is an Atrioventricular valve, also known as the bicuspid valve because of two cups.|
|Location||Aortic valve originates between the left ventricle and the aorta.||Mitral valve is placed between the left atrium and the left ventricle.|
|Function||Aortic valve regulates the movement of blood from left ventricle to the aorta and prevents backflow of blood.||Mitral valve controls the blood flow from left atrium to the left ventricle and stops backflow of blood starting from the ventricle to the atrium.|
|Blood supply||In Aortic valve, the flow of blood is from the left ventricle to the aorta.||In Mitral valve, the blood flows from the left atrium to the left ventricle.|
|Structure||The Aortic valve is made up of three cusps (membranes); the valve is located on the muscle ring and it is connected to the heart wall.||The Mitral valve is composed of two cusps or leaflets attached to the papillary muscles of the heart by chordae tendineae.|
|Diseases||The Aortic valve disease is the most common. It involves tightening of the aortic valve.||Most common conditions include Mitral valve collapse and Mitral valve regurgitation.|
What is an Aortic Valve?
The Aortic valve is one of the four valves that the heart has. It connects the left ventricle to the aorta. The Left Ventricle forces the oxygenated blood to get distributed in all parts of your body through the Aortic valve. The Aorta is the artery that carries the oxygenated blood to the body parts. Therefore, the Aortic valve regulates the oxygen-rich blood flow into the aorta and ensures that the blood keeps flowing in one direction.
The Aortic valve is a Semilunar valve (consisting of three cusps) that connects the heart ventricles to the arteries.
Structure and Function of the Aortic Valve
- The Aortic valve generally has three cusps or leaflets, but their names are inconsistent. Anatomists have named them- the left posterior (origin of the left coronary), anterior (the source of the right coronary) and right posterior. They may also be named- the left coronary, right coronary and non-coronary cusp.
- The three cusps contain the aortic sinus when the valve is closed. The root of coronary arteries is discovered in two of these cusps. The width of the aortic sinus is more than the left ventricular tract and the aorta. The intersection of the sinuses with the aorta is anointed the sinotubular junction.
- The aortic valve is pin-pointed near the pulmonary valve and the joint where the two anterior cusps link together points toward the pulmonary valve.
- The aortic valves appear like an 'umbrella'. During diastole, the shape of the cusps and the aortic root trigger the cusps and shut the aortic valve. This procedure controls the reverse blood flow into the left ventricle.
- The sinuses ensure that the openings of the coronary arteries are not blocked when the aortic valve cusps are unobstructed.
Conditions affecting the Aortic Valve
There are a few conditions that can affect the aortic valve. Some of the conditions include:
- Aortic Valve Stenosis- It is a type of heart valve disease. It includes the narrowing of the valve between the lower left heart chamber and the body's main artery (aorta). Due to this, the blood flow from the heart to the aorta and the body gets obstructed. Its symptoms include:- Chest pain, shortness of breath, fluttering and rapid heartbeat, fatigue, and the feeling of not wanting to eat enough.
- Aortic Valve Regurgitation- This situation arises when the aortic does not close tightly. Due to this, some of the blood, which emits out of the central pumping chamber, the left ventricle gets leaked backwards.
- Endocarditis- Endocarditis is a rare and deadly infection that affects the internal lining of the heart's chambers and valves. Without early treatment, it can ruin the valves of the heart.
What is Mitral Valve?
The mitral valve is one of the two atrioventricular heart valves. It is also known as the bicuspid valve as it has only two cusps. The mitral valve is sited between the left atrium and the left ventricle of the heart. It stops the blood from getting leaked into the atrium during systole. During contraction, blood flows through an open mitral valve with contraction of the left atrium. During systole, the mitral valve shuts with the compaction of the left ventricle. Now, let’s have a look at the functions and structure of the Mitral valve.
Structure and Function of the Mitral Valve
- The mitral valve is found in the left part of the heart, between the left atrium and the left ventricle. It must be 4 to 6 square centimeters in its area.
- Unlike the Aortic valve, the Mitral valve consists of two leaflets or cusps- an anteromedial leaflet and a posterolateral leaflet. Mitral cusps thickness is usually about 1 mm though occasionally can vary from 3–5 mm.
- The chordae tendineae present in the mitral valve prevents the valve cusps from collapsing into the left atrium. The entrance of the mitral valve is surrounded by a fibrous ring known as the mitral annulus.
- After the pressure falls in the left ventricle due to the relaxation of the ventricular myocardium, during the left ventricular diastole, the mitral valve gets opened, allowing the blood to travel beginning the left atrium to the left ventricle.
- During left atrial systole, the blood flows immediately across the mitral valve before the left ventricular systole. This flow through the open mitral valve is seen in the echocardiography as the A wave.
Diseases of mitral Valve and their causes
- Mitral valve prolapse:- This is a condition in which the mitral valve's flaps become so limp that they become incapable to shut appropriately. The problem is that if the valves do not close smoothly, they may bulge upwards towards the left atrium. Due to this, the blood can leak back via the valve and into the left atrium. Professionals sometimes name it Barlow's syndrome. The most typical cause of Mitral valve prolapse is floppy and springy valve cusps or flaps. Endocarditis (an infection in the internal lining of the heart) may also cause Mitral Valve Prolapse.
- Mitral regurgitation:- This is described as the situation in which the valves are not shutting adequately. It can also drive the blood to leak back through the valve every time the left ventricle contracts. If left untreated, Mitral Regurgitation can lead to various heart-related problems like high blood pressure, an irregular heartbeat, and heart failure. It can result from floppy valves or if the ring surrounding the valve becomes too broad. Any damage caused to the mitral valve or the tissue chords of the heart can also cause Mitral Regurgitation.
- Mitral valve stenosis:- Mitral valve stenosis includes the narrowing or blocking of the mitral valve opening. In other words, it happens when the mitral valve does not open as much as it must. This restriction leads to a decrease in the quantity of oxygen-rich blood that is carried from the lungs. There are several reasons which can cause this condition: rheumatic fever, lupus, congenital heart defects, etc. Rheumatic fever is the common cause of MVS.
Main Differences Between Aortic Valve and Mitral Valve (In Points)
- The first difference is their location. The aortic valve is set between the left ventricle and the left aorta. The Mitral valve is found between the left ventricle and the left atrium.
- The next difference is the number of flaps they have- The Aortic valve has three flaps or cusps whereas, the Mitral valve is the only valve consisting of two flaps. Flaps perform a crucial role in preventing the backflow of blood.
- The flow of blood in the Aortic valve is from the left ventricle to the aorta. The outpour of blood in the Mitral valve is from the left atrium to the left ventricle.
- The Aortic valve is located on the muscle ring and is attached to the heart wall. The Mitral valve is made up of two cusps or leaflets attached to the papillary muscles of the heart by chordae tendineae.
- The role of the valves is to flow blood through the heart. When the two atrium chambers contract, the tricuspid and mitral valves open, allowing the blood to transfer to the ventricles. When the two ventricle chambers contract, they compel the tricuspid and mitral valves to close as the pulmonary and aortic valves open.
Understanding the anatomy of the heart can be a little tricky and complex. The heart is divided into four chambers- two atrioventricular valves and two Semilunar valves. Where the Mitral valve is under the atrioventricular valves category, on the other hand, the Aortic hand is categorised under Semilunar valves.
Both Aortic and Mitral valves are located differently and have distinct functions to perform. The Aortic valve carries blood between the left ventricle and the corresponding aorta. The Mitral valve carries blood between the left ventricle and the left atrium. They both make sure the blood flows properly and does not back into the other sections of the heart. The valves are extremely important in the adequate flow of blood in the body.
Although, the process of blood flow is very complex, hopefully, this article helped in improved comprehension of the differences between the Aortic valve and the mitral valve.