From there it is pumped into the lungs via the pulmonary trunk and right semilunar valve. The freshly oxygenated blood is then carried by pulmonary veins to the left side of the heart. The left side of the heart is known as the systemic circuit pump . This is because the left side of the heart is in change of pumping blood to the entire body. Freshly oxygenated blood leaves the lungs and returns to the left atrium in the pulmonary vein.
Blood then passes through the bisucpid valve to the left ventricle.
From there it is on to the body, but first it must pass through the left semilunar valve. This whole cycle repeats itself continuously.