Semilunar valves

Classically, vegetations typically are located on the line along valve closure on the atrial surface of the atrioventricular valves (tricuspid and mitral) or on the ventricular surface of the semilunar valves (pulmonary and aortic) (Fig. 71-2). The vegetations can vary significantly in size from only millimeters to several centimeters and may be single or multiple masses. Often, destruction of underlying tissue occurs and may cause... 

The semilunar valves separate the ventricles from their associated arteries. The pulmonary valve is found between the right ventricle and the pulmonary artery and the aortic valve is found between the left ventricle and the aorta. These valves prevent backward flow of blood from the pulmonary artery or the aorta into their preceding ventricles when the ventricles relax. The semilunar valves also have three cusps. There are no valves between the venae cavae or the pulmonary veins and the atria into which they deliver blood. The closure of the valves causes the "lub-dub" associated with the heart beat. Tire first heart sound, or the "lub," occurs when the ventricles contract and the AV valves close. The second heart sound, or the "dub," occurs when the ventricles relax and the semilunar valves close. 

From the AV node, the electrical impulse spreads through the AV bundle or the bundle of His. This portion of the conduction system penetrates the fibrous tissue separating the atria from the ventricles and enters the interventricular septum where it divides into the left and right bundle branches. The bundle branches travel down the septum toward the apex of the heart and then reverse direction, traveling back toward the atria along the outer ventricle walls. This route of conduction of the impulse facilitates ejection of blood from the ventricles. If the impulse were to be conducted directly from the atria to the ventricles, the ventricular contraction would begin at the top of the chambers and proceed downward toward the apex. This would trap the blood at the bottom of the chambers. Instead, the wave of ventricular electrical stimulation and, therefore, contraction moves from the apex of the heart toward the top of the chambers where the semilunar valves are located and ejection takes place. 

Then heart Pericardium, atrium, ventricle, ventricular septum, atrioventricular valve, and semilunar valve. 

Q2 The AV valve on the right side of the heart is the tricuspid valve. It has three cusps and is located between the right (R) atrium and the R ventricle. In addition there are semilunar valves at the entrance to both the aorta and the pulmonary artery. 

DUP, is due to closure of the semilunar valves in the outflow vessels from the ventricles, the aorta and pulmonary artery. 

There are two sets of heart valves the AV valves between atria and ventricles and the semilunar valves at the entrance to the pulmonary artery and aorta. Closure of these valves produces the first and second heart sound. Valves may become distorted and incompetent following infections such as rheumatic fever, leading to backflow of blood and abnormal heart sounds, or murmurs. 

The heart has four valves— two atrioventricular (tricuspid and mitral) and two semilunar (pulmonic and aortic). Atrioventricular valves control bloodflow between the atria and ventricles. Semilunar valves control the bloodflow between the ventricles and the pulmonary artery and the aorta. 

The human heart contains four unidirectional valves that are anatomically grouped into two types the atrioventricular valves and the semilunar valves. The tricuspid and mitral (bicuspid) valves... 

Check the cardiac valves. The tricuspidal atrioventricular valve on the right side comprises three cusps. The mitral AV valve on the left side comprises two cusps. Both AV valves are linked to papilla-shaped muscles via tendinous ligaments. The pulmonal and aortic valves also have three semilunar cusps, respectively. 

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