Difference Between Mitral Valve and Tricuspid Valve

Key Difference – Mitral Valve vs Tricuspid Valve
 

Heart valves are very important as they allow a unidirectional flow of blood to and from the heart. This ensures that the blood circulation takes place in an efficient manner. There are four main valves that are involved in blood circulation in mammals. They are the two atrioventricular valves; the mitral valve and the tricuspid valve and the two semilunar valves; the aortic valve and the pulmonary valve. The mitral valve is the valve located in between the left atrium and the left ventricle. Also known as the Bicuspid valve as it is composed of two cusps. The tricuspid valve is the valve located in between the right atrium and the right ventricle. The tricuspid valve is composed of three cusps. The key difference between the mitral valve and the tricuspid valve is the number of cusps. Mitral valve is composed of two cusps whereas the tricuspid valve is composed of three cusps.

CONTENTS

1. Overview and Key Difference
2. What is Mitral Valve
3. What is Tricuspid Valve
4. Similarities Between Mitral Valve and Tricuspid Valve
5. Side by Side Comparison – Mitral Valve vs Tricuspid Valve in Tabular Form
6. Summary

What is Mitral Valve?

The mitral valve or the bicuspid valve is known as the left atrioventricular valve. It is composed of two flaps thus named as the bicuspid valve. The valve lies between the left atrium and the left ventricle. The blood flow is controlled by the mitral valve. In normal conditions, the blood flows through the open mitral valve when the left atrium contracts. When the blood enters the left ventricle and the ventricular contraction takes place and the mitral valve closes. When the left ventricular pressure increases, the mitral valve closes. Thus, the mitral valve prevents the reverse flow of blood from the left ventricle to the left atrium.

The mitral valve has a rough area of about 4-6 cm² and resides in the left heart. The valve is composed of two leaflets or two cusps. The two leaflets are termed as an anteromedial leaflet and posterolateral leaflet. The opening of the mitral valve is surrounded by a fibrous ring that is known as the mitral annulus.

Figure 01: Mitral Valve

Under abnormal conditions, if the mitral valve is narrowed or abnormally developed, blood may flow back resulting in heart diseases. Rheumatic heart diseases are often related to the abnormalities of the mitral valve.

What is Tricuspid Valve?

Tricuspid valve or the right atrioventricular valve is between the right atrium and the right ventricle and controls the blood flow. The tricuspid valve is situated on the dorsal side of the mammalian heart. It has three leaflets or three cusps and three papillary muscles. In certain instances, the tricuspid valve can also contain, two or four leaflets. The main function of the tricuspid valve is to prevent the backflow of blood from the right ventricle to the left ventricle.

Figure 02: Tricuspid Valve

Abnormalities of the tricuspid valve or infections of the tricuspid valve can lead to an uncontrolled backflow of blood. It is also associated with rheumatic heart diseases.

What are the Similarities Between Mitral Valve and Tricuspid Valve?

• Both Mitral Valve and Tricuspid Valve are situated between the atrium and the ventricles, thus termed as atrioventricular valves.
• Both Mitral Valve and Tricuspid Valve prevent the backflow of blood to the atria.
• Both Mitral Valve and Tricuspid Valves act as controlling mechanisms for the efficient circulation of blood.
• Abnormalities of both Mitral Valve and Tricuspid Valves result in rheumatic heart diseases.

What is the Difference Between Mitral Valve and Tricuspid Valve?

Summary – Mitral Valve vs Tricuspid Valve

The heart valves are mainly involved in the control of blood flow from the heart. There are four main valves involved in regulation of the blood circulation. The atrioventricular valves which include the mitral valve and the tricuspid valve control the blood flow from the atrium to the ventricle. The mitral valve or the bicuspid valve is involved in controlling the blood flow from the left atrium to the left ventricle. The tricuspid valve is situated in between the right atrium and the right ventricle. The mitral valve and the tricuspid valve differ in the number of leaflets or cusps they possess. Mitral valve is composed of two cusps and hence, is referred to as bicuspid valve, whereas the tricuspid valve has three cusps. This is the difference between Mitral valve and Tricuspid valve.

Reference:

1.Khan, Ijaz A. “Ebstein’s Anomaly of the Tricuspid Valve with Associated Mitral Valve Prolapse.” Texas Heart Institute Journal, U.S. National Library of Medicine, 2001. Available here
2.“The Valves of the Heart.” TeachMeAnatomy, 22 Dec. 2017.  Available here  

Image Courtesy:

1.’Blausen 0460 Heart VentriclesRelaxed’By Blausen Medical Communications, Inc. – Donated via OTRS, see ticket for details, (CC BY 3.0) via Commons Wikimedia 
2.’Atrioventricularvalve’ (Public Domain) via Commons Wikimedia

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