What is the pulmonary valve?
The pulmonary valve (one of two semilunar valves in the heart), also known as the pulmonic valve, is the valve that is situated between the right ventricle chamber and the pulmonary artery, which is responsible for transporting deoxygenated blood to the lungs from the heart.
It is called the pulmonary valve because it leads to the pulmonary artery. The pulmonic valve, like the tricuspid valve and aortic valve, has three cusps or leaflets (generally it is only the bicuspid/mitral valve that has two leaflets) that open and close to regulate blood flow and prevent blood from leaking back (regurgitating) into the right ventricle.
What does the pulmonary valve look like?
The average size of a pulmonic valve in adults is 2.5 cm². The three leaflets of the valve – the left cusp, right cusp, and the anterior cusp – attach to the ventricular septum (the wall that separates the heart’s lower chambers) and the pulmonary annulus, a fibrous ring similar to that of the aortic valve.
Unlike the tricuspid and mitral valves, the pulmonary valve is not supported by heart strings. The leaflets resemble half-moons and each cusp has a free edge and small fibrous nodule at the center of it. Like the aortic valve, there is also a supportive rim (lunula) that ensures tight closure of the valve.
What is the function of the pulmonary valve? How does it function?
The pulmonic valve of the heart serves the function of regulating blood that flows between the right ventricle (this is the heart’s bottom right chamber) and the pulmonary artery. It also prevents regurgitation as blood is pumped from the right ventricle to the pulmonary artery.
Normally, pressure increases in the right ventricle during ventricular systole (contraction). Once pressure in the ventricle exceeds pulmonary pressure, the pulmonary valve opens, allowing blood to pass through from the right ventricle to the pulmonary artery. Then, as soon as ventricular systole ends, pressure drops rapidly and pulmonary pressure forces the pulmonic valve shut.
What happens when the pulmonary valve doesn’t function properly?
If the pulmonic valve is in some way defective or damaged, dysfunction can occur within the heart and body. This can cause a variety of symptoms and complications.
Pulmonary valve disease is rare. When there are problems, it is usually due to a congenital abnormality that is present from birth, such as pulmonary atresia (where the valve’s orifice fails to develop), Tetralogy of Fallot, or great transposition of the arteries, or double outlet right ventricle.
Pulmonary valve stenosis and pulmonary valve regurgitation are two potentially serious problems that are associated with congenital conditions. They can develop later on in life, however, due to rheumatic heart disease, carcinoid syndrome, infective endocarditis, etc.