Similar to the aortic valve,[1] the pulmonary valve opens in ventricular systole when the pressure in the right ventricle rises above the pressure in the pulmonary artery.

At the end of ventricular systole, when the pressure in the right ventricle falls rapidly, the pressure in the pulmonary artery closes the pulmonary valve.

The closure of the pulmonary valve contributes to the P2 component of the second heart sound (S2).

[3] At the apex of the infundibulum, the pulmonary orifice is guarded by three semilunar cusps - two anterior and one posterior, with free edges projecting upward into the lumen of pulmonary trunk.

However, it is physiologically normal in some young people to hear both components separated during inhalation.