Time of pulmonary circulation

The circulatory system of the lungs is the portion of the cardiovascular system in which oxygen-depleted blood is pumped away from the heart, via the pulmonary artery, to the lungs and returned, oxygenated, to the heart via the pulmonary vein.

Pulmonary circulation transports oxygen-poor blood from the right ventricle to the lungs, where blood picks up a new blood supply. Then it returns the oxygen-rich blood to the left atrium.

Oxygen deprived blood from the superior and inferior vena cava enters the right atrium of the heart and flows through the tricuspid valve (right atrioventricular valve) into the right ventricle, from which it is then pumped through the pulmonary semilunar valve into the pulmonary artery to the lungs. Gas exchange occurs in the lungs, whereas CO2 is released from the blood, and oxygen is absorbed. The pulmonary vein returns the now oxygen-rich blood to the left atrium.

Reduced or increased time of pulmonary circulation may be caused by existing inflammations, increasing of pressure in lungs capillaries, changes of rheological characteristics of blood, etc.

References:

https://en.wikipedia.org/wiki/Pulmonary_circulation

https://training.seer.cancer.gov/anatomy/cardiovascular/blood/pathways.html