Valves are needed to prevent blood flowing backwards into the heart.
The entrance to the ascending aorta is guarded by the semilunar valve. The semilunar valves are pocketlike structures attached at the point at which the pulmonary artery and the aorta leave the ventricles.
ventricles
The upper heart valves are called atriums, and the lower heart valves are called ventricles.
Atrioventricular valves ar the valves in the heart that lie between the atria and the ventricles. These valves stop the the blood from flowing back (in the wtong direction) from the ventricles into the atria. There are two atrioventricular valves, on the right is the Tricuspis and on the left is the Bicuspid or Mitral valve.
As the ventricles of the heart contract the pressure in the ventricles rises beyond that of the atria. This pressure differential causes the AV valves to shut.
The valves in the auricles (atria) and ventricles of the heart ensure unidirectional blood flow throughout the cardiac cycle. The atrioventricular valves (tricuspid and mitral) prevent backflow of blood from the ventricles to the atria during contraction, while the semilunar valves (pulmonary and aortic) prevent backflow from the arteries into the ventricles during diastole. This coordinated function is crucial for efficient circulation and maintaining proper blood pressure within the heart and vessels.
The entrance to the ascending aorta is guarded by the semilunar valve. The semilunar valves are pocketlike structures attached at the point at which the pulmonary artery and the aorta leave the ventricles.
Pulmonary and aortic valves are semilunar valves having three semilunar cusps each. these valves open with the free ends facing the vessels when the heart contracts and closes when heart relaxes thus preventing regurgitation
When the ventricles are relaxed, the semilunar valves are closed, while the atrioventricular (AV) valves are open. This allows blood to flow from the atria into the ventricles. The closure of the semilunar valves prevents backflow of blood from the arteries into the ventricles during this phase.
There are no valves between the atria. The valves between the atria and ventricles close when the ventricles contract.
As the ventricles of the heart contract the pressure in the ventricles rises beyond that of the atria. This pressure differential causes the AV valves to shut.
Atrio-ventricular valves
The semilunar valves, located at the exit of the heart's ventricles, consist of the aortic and pulmonary valves. They prevent backflow of blood into the ventricles after contraction. When the ventricles contract, the increased pressure forces the valves open, allowing blood to flow into the aorta and pulmonary artery. Once the ventricles relax, the pressure drops, causing the valves to close and prevent blood from returning to the heart.
ventricles
The atrioventricular valves.
The valves that control the exits of the ventricles are called semilunar valves. There are two semilunar valves: the aortic valve, which regulates blood flow from the left ventricle into the aorta, and the pulmonary valve, which controls blood flow from the right ventricle into the pulmonary artery. These valves prevent backflow of blood into the ventricles after contraction.
It means "atrioventricular". It refers to the valves between the atria and the ventricles.