The right ventricle pumps blood through the pulmonary semilunar valve into the pulmonary trunk, which is just a big vessel that splits to form the left and right pulmonary arteries.

右心室通过肺半月瓣将血液泵入肺动脉干，肺动脉干只是一个大血管，它分裂形成左右肺动脉。