Difference between AV Valves and Semilunar Valves

AV Valves and Semilunar Valves are the two types of Valves that help in blood flow regulation. The heart’s atrioventricular (AV) Valves are unique Valves that are essential for controlling blood flow between the ventricles, which are the lower chambers, and the atria, which are the upper chambers. An individual’s heart contains two AV Valves Tricuspid and Bicuspid Valves.

To maintain a unidirectional flow of blood through the heart, the opening and shutting of AV Valves is synchronized with the cardiac cycle. The human heart contains two Valves called Semilunar Valves, which are positioned at the ventricle exits and are essential for controlling blood flow out of the heart. Just like AV Valves, Semilunar Valves are also of two types including pulmonary and aortic Valves.

Difference Between AV Valves and Semilunar Valves

The two types of heart Valves that are most important in controlling blood flow within the heart are Semilunar and atrioventricular (AV) Valves. These are the differences between Semilunar and AV valves.

Category	AV Valves	Semilunar Valves
Full Form	Tricuspid and Bicuspid Valves	Pulmonary and aortic Valves
Location	These are located between the atria and ventricle of heart. Tricuspid on the right side and Bicuspid on the left side.	These are present in ventricle exits. The pulmonary Valve is present at the right ventricle exit and the aortic Valve is present at the left ventricle exit.
Structure	Both the bicuspid and tricuspid Valves have two and three cusps, respectively, and are connected to chordae tendineae fibrous cords that link the Valvesalve cusps to the papillary muscles in the ventricles.	The aortic and pulmonary have three Semilunar-shaped cusps are present in Valvesalves. Unlike AV valves, they lack chordae tendineae and papillary muscles.
Functions	Preventing blood from flowing backward from the ventricles into the atria during ventricular contraction, or systole, is an important role of AV Valves.	During ventricular relaxation, these Valves stop blood from flowing backward from the arteries into the ventricles (diastole).

What are Heart Valves?

Blood flow is regulated by the heart, Valves which are specialized structures located within the heart. Blood can circulate efficiently because these Valves guarantee that blood flows through the heart chambers only in one direction. The human heart consists of four major cardiac Valves: Tricuspid, Bicuspid Valves (AV Valves), pulmonary, and aortic Valves (Semilunar Valves). The cardiac cycle is synchronized with the opening and shutting of the heart Valves. The AV Valves open to permit blood to enter the ventricles during atrial contraction, also known as Valves. The Semilunar Valves open to let blood exit into the pulmonary artery and aorta during ventricular systole, or contraction of the ventricles. The AV Valves seal to stop blood from flowing backward into the atria.

What are AV Valves?

The atrioventricular (AV) Valves of the heart are specialised Valves that are necessary for regulating blood flow between the atria, or upper chambers, and the ventricles, or lower chambers. Two AV Valves, such as the bicupsid and tricupsid valves, are present in each individual’s heart. The AV Valves open and close in time with the cardiac cycle to ensure a one way flow of blood through the heart. When the ventricles contract, blood flows into the atria through the AV Valves, which close during ventricular contraction and open during atrial contraction. For enough circulation to continue and to stop blood from flowing backward into the heart chambers, the AV Valves must operate properly. Diseases like regurgitation or stenosis can result from these Valves malfunctions, which can lower the heart pump’s overall effectiveness.

What are Semilunar Valves?

To regulate blood flow out of the heart, the human heart has two valves called Semilunar Valves that are located at the ventricle outputs. Semilunar Valves, pulmonary and aortic Valves are of two types, just like AV Valves. The Valves cusps‘ half-moon form is referred to as “Semilunar” shape. The chordae tendineae and papillary muscles of Semilunar Valves are absent from AV Valves. Their ability to open and shut is instead dependent on variations in ventricular pressure.

Blood must continue to flow out of the heart in a single direction and cannot return back into the ventricles if the Semilunar Valves are not working properly. These Valve diseases can impair the effectiveness of the heart pump and circulation as a whole. Examples of these diseases include aortic or pulmonary Valve stenosis or regurgitation.

Functions of Heart Valves

Heart Valves are responsible for controlling and ensuring that blood flows through the heart only in one direction. In coordination with the contractions of the heart chambers, the heart Valves function like gates or doors that open and close at certain points during the cardiac cycle. Heart valves may be classified into two primary types: Semilunar Valves and atrioventricular (AV) Valves.

1. Enabling the proper direction of blood flow from one cardiac chamber to another.
2. keeping the blood from flowing backward between the heart’s chambers while the heart cycles.
3. Helping the heart pump blood in a single direction, which is vital for keeping the body’s tissues and organs oxygenated and circulated effectively.

Disorders of Heart Valves

Conditions, when one or more heart Valves malfunction are referred to as heart Valve disorders. Heart Valve problems come in several forms and can impact either the Semilunar or atrioventricular (AV) valves. Heart Valve conditions that are common include:

1. Stenosis: Reduced blood flow through a heart Valve due to constriction or narrowing of the Valve is called stenosis.
2. Regurgitation: Blood might seep backward through a heart Valve when it should be closed, a condition known as regurgitation.
3. Prolapse: When ventricular contraction causes a Valve’s flaps, typically the mitral Valve, to prolapse, the valve collapses or bulges backward into the atrium.
4. Endocarditis: An infection of the inner lining of the heart chambers or the heart Valves is known as endocarditis.
5. Congenital heart Valve disorder: Some people have abnormally shaped or malfunctioning cardiac Valves from birth.
6. Rheumatic Cardiac diseases: Untreated Streptococcal infections can cause rheumatic fever, which can cause inflammation and damage to the heart Valves.

FAQs – AV Valves and Semilunar Valves

What is the Difference Between the AV Valves and the Semilunar Valves Function?

AV Valves (mitral and tricuspid) separate atria from ventricles, while SL Valves (aortic and pulmonary) divide ventricles from major arteries. AV Valves have leaflets; SL Valves have cusps.

Is Semilunar Valve Same as Aortic Valve?

The aortic Valve, one of the four heart Valves, marks the endpoint for oxygenated blood leaving the heart. It is named the aortic Semilunar Valve owing to its distinctive Semilunar shape.

What is Another Name for the Semilunar Valves?

Heart sounds primarily comprise two distinct sounds produced when the atrioventricular Valves (mitral and tricuspid) and Semilunar Valves (aortic and pulmonary) close.

What is the Difference Between the Atrioventricular Valve and the Tricuspid Valve?

The tricuspid Valve, one of the heart’s four Valves, situated between the right ventricle and right atrium, ensures proper blood flow direction by opening and closing as the right atrioventricular Valve.

What is the Function of the AV Semilunar Valves?

Semilunar Valves prevent blood backflow from arteries to ventricles during ventricular diastole, maintaining pressure on major arteries. The aortic Semilunar Valve separates the left ventricle from the aorta opening.

What are the 2 Atrioventricular Valves?

The mitral and tricuspid Valves, also called atrioventricular Valves, are positioned between the heart’s upper chambers (atria) and lower chambers (ventricles).

Why is called Semilunar Valve?

Semilunar Valves derive their name from the crescent moon shape of their flaps. These valves control the flow of the blood out of the heart and is situated at the ventricle output.

What is Another Name for the Right AV Valve?

The tricuspid Valve, or the right atrioventricular Valve, is named for its three cusps, which are leaflet-shaped flaps that aid in sealing the Valve.