The primary function of pulmonary circulation in human is oxygenation of blood. This pathway does not include

Left ventricle pumps blood to systemic circulation.

Pulmonary circulation pathway:

Right atrium $\to$Deoxygenated blood $\to$Right ventricle $\to$Pulmonary trunk $\to$Lungs $\to$Oxygenated blood $\to$Pulmonary veins $\to$Left atrium