This endocardium lines the heart chambers as well as the heart valves.

心内膜覆盖了心脏各腔室和瓣膜。

These are the heart chambers that receive blood returning to the heart.

它们是接收血液返回心脏的心腔。

These are the heart chambers that pump blood out of the heart.

它们是从心脏泵出血液的心腔。