肺循环动脉血从心脏流向肺微血管静脉血从肺微血管流回心脏两者合称肺循环
Arterial blood in the pulmonary circulation flows from the heart to the pulmonary microvessels, and venous blood flows from the pulmonary microvessels back to the heart. The two together are called pulmonary circulation
以上为机器翻译结果，长、整句建议使用 人工翻译 。