AV Valves vs. Semilunar Valves — What's the Difference?
By Tayyaba Rehman — Published on November 24, 2023
AV valves (atrioventricular valves) regulate blood flow between atria and ventricles, while semilunar valves control blood exit from the ventricles to pulmonary/aorta.
Difference Between AV Valves and Semilunar Valves
Table of Contents
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Key Differences
AV Valves, or atrioventricular valves, are integral to maintaining a one-way blood flow from the atria to the ventricles. Semilunar Valves, on the other hand, oversee the flow from the ventricles to the pulmonary artery and aorta. Both sets of valves ensure unidirectional blood flow, preventing backflow and maintaining separate pathways for oxygenated and deoxygenated blood.
AV Valves, consisting of the tricuspid and mitral valves, are characterized by their flaps or 'cusps'. Semilunar Valves, including the pulmonary and aortic valves, are shaped like half-moons and have three cusps. Both types are crucial for the synchronized and sequential contractions that underpin the cardiac cycle.
AV Valves demonstrate unique opening and closing mechanics, related to the pressure changes during the cardiac cycle. Contrarily, Semilunar Valves operate by preventing backflow of blood into the ventricles post-ejection, exhibiting a different, albeit equally crucial, mechanical role in cardiac function.
When AV Valves are in focus, it’s crucial to understand their attachment to papillary muscles via chordae tendineae, which prevent eversion. Semilunar Valves lack these structures but efficiently seal the ventricular outlets during diastole, demonstrating a different anatomical and functional structure.
Diseases affecting AV Valves, like mitral valve prolapse, impact the communication between atria and ventricles. In contrast, disorders affecting Semilunar Valves, like aortic stenosis, typically affect the flow of blood from the ventricles to the major arteries, indicating both can be compromised but with different physiological implications.
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Comparison Chart
Location
Located between atria and ventricles
Located between ventricles and arteries (pulmonary artery & aorta)
Components
Comprise of the tricuspid (right side) and mitral/bicuspid (left side) valves
Include the pulmonary valve (right side) and aortic valve (left side)
Function
Prevent backflow of blood from ventricles to atria during ventricular contraction
Prevent backflow of blood from arteries (pulmonary & aorta) back into the ventricles
Leaflets/Cusps
Tricuspid has 3 leaflets; mitral/bicuspid has 2
Both pulmonary and aortic valves have 3 cusps
Associated Structures
Attached to papillary muscles via chordae tendineae
Do not have chordae tendineae attachments
Compare with Definitions
AV Valves
AV Valves facilitate blood flow from the atria to ventricles.
The AV Valves close during ventricular systole to prevent backflow.
Semilunar Valves
Semilunar Valves prevent backflow into ventricles during diastole.
A defective semilunar valve can result in diastolic murmurs.
AV Valves
AV Valves are anchored by chordae tendineae.
During cardiac surgery, the integrity of the AV Valves’ chordae tendineae must be preserved.
Semilunar Valves
Semilunar Valves encompass the pulmonary and aortic valves.
The semilunar valves ensure that blood is ejected into the pulmonary artery and aorta during systole.
AV Valves
AV Valves' dysfunction can result in atrioventricular regurgitation.
Patients with defective AV Valves may exhibit audible heart murmurs.
Semilunar Valves
Semilunar Valves don't have chordae tendineae.
Unlike AV Valves, semilunar valves function without the need for anchoring structures like chordae tendineae.
AV Valves
AV Valves include the mitral and tricuspid valves.
AV Valves demonstrate distinct structural differences between their right and left counterparts.
Semilunar Valves
Semilunar Valves have three cusps shaped like half-moons.
Malformations of the semilunar valves' cusps can lead to valvular disorders.
AV Valves
AV Valves are critical for preventing retrograde blood flow during ventricular contraction.
Stenosis of the AV Valves can result in compromised cardiac efficiency.
Semilunar Valves
Semilunar Valves’ stenosis impacts ejection of blood into major arteries.
Stenosis of the semilunar valves may warrant surgical intervention, like valve replacement.
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Written by
Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
