From the lungs, freshly oxygenated blood flows back into the left atrium and passively passes through the mitral or bicuspid valve to fill the left ventricle.

新鲜的含氧血液从肺部流回左心房，被动地通过二尖瓣（bicuspid valve）注入左心室。

Oxygenated blood returns to the heart by way of pulmonary veins, which empty into the left atrium. Atrial contractions force blood from the left atrium through the mitral valve, also called bicuspid valve, into the left ventricle.

当心室收缩时，左室内血液经主动脉瓣流入主动脉¬----人体最大的动脉，为全身组织供血。