Difference Between AV Valves and Semilunar Valves

The key difference between AV valves and semilunar valves is that the AV valves allow blood to flow from atria to ventricles while the semilunar valves allow blood to flow from ventricles to arteries that emerge from the ventricles.

The heart is a muscular organ that circulates blood throughout our body via the circulatory system. It provides oxygen and other nutrients to all parts of our body and cleans our body by removing metabolic wastes. The human heart has four chambers; two atria (left atrium and right atrium) and two ventricles (left ventricle and right ventricle). There are four heart valves that allow blood to flow in one direction through the heart. They are two atrioventricular (AV) valves (mitral valve and tricuspid valve) and two semilunars (SL) valves (aortic valve and pulmonary valve). Mitral valve and aortic valve located in the left side of the heart while the tricuspid valve and pulmonary valve located in the right side of the heart.

CONTENTS

1. Overview and Key Difference
2. What are AV Valves
3. What are Semilunar Valves
4. Similarities Between AV Valves and Semilunar Valves
5. Side by Side Comparison – AV Valves vs Semilunar Valves in Tabular Form
6. Summary

What are AV Valves?

AV valves are the two heart valves that lie between atria and ventricles. There are two AV valves namely, the mitral valve and tricuspid valve. Mitral valve is also known as bicuspid valve locates in the left side of the heart between the left atrium and left ventricle. On the other hand, the tricuspid valve locates between the right atrium and right ventricle.

As the names mentioned, the bicuspid valve has two cusps while the tricuspid valve has three leaflets. Prevention of backflow of blood from the left ventricle to the left atrium is the main function of the mitral valve. The function of the tricuspid valve is to block the backflow of blood from the right ventricle into the right atrium. Therefore, the overall function of the AV valves is the allowing blood to flow from atria into ventricles and prevent the backflow.

What are Semilunar Valves?

Semilunar valves are the heart valves present between ventricles and the arteries emerge from the ventricles. There are two valves namely pulmonary valve and aorta valve. Both valves have three cusps. The pulmonary valve has left, right, and anterior cusps while the aortic valve has left, right, and posterior cusps.

Pulmonary artery locates between the right ventricle and the pulmonary artery. Aorta valve is present between the left ventricle and the aorta. Both types of valves open during the ventricular systole. The function of these valves is to permit blood to be forced into the arteries and prevent backflow from the arteries into the ventricles.

What are the Similarities Between AV Valves and Semilunar Valves?

• AV Valves and Semilunar Valves are heart valves.
• They prevent backflow of blood.
• Both facilitate one direction of blood flow through the heart.
• They open and close at the right time.

What is the Difference Between AV Valves and Semilunar Valves?

AV Valves and Semilunar Valves are two types of heart valves. AV valves are present between atria and ventricles, and they prevent the backflow of blood from ventricles to atria. On the other hand, semilunar valves are present between ventricles and arteries emerge from the ventricles, and they prevent the backflow of blood from the arteries to ventricles. Both types of these valves facilitate the directed flow of blood through the heart. The below infographic presents the difference between AV valves and semilunar valves in tabular form.

Summary – AV Valves vs Semilunar Valves

Heart valves regulate the blood flowing through the heart. There are four valves in the heart. Two valves are present in the left heart while another two are in the right heart. Two AV valves are the mitral valve and tricuspid valve. Two semilunar valves are the aortic valve and the pulmonary valve. AV valves lie between the atria and the ventricles of the heart while semilunar valves locate between ventricle and arteries emerge from ventricles. AV valves prevent blood flow from ventricles to atria while semilunar valves prevent blood flow from arteries to ventricles. This is the difference between AV valves and semilunar valves.

Reference:

1.“Heart Valve.” Wikipedia, Wikimedia Foundation, 14 Aug. 2018. Available here 

Image Courtesy:

1.”2011 Heart Valves”By OpenStax College – Anatomy & Physiology, Connexions Web site, Jun 19, 2013., (CC BY 3.0) via Commons Wikimedia
2.”Diagram of the human heart (cropped)”By Wapcaplet – Own work, (CC BY-SA 3.0) via Commons Wikimedia