The coronary arteries start up in the epicardium, and then dive down and supply all the heart tissue.

冠状动脉在心外膜发出，然后深入供应所有心脏组织。

The muscle is enclosed on the outside by the epicardium and on the inside by the endocardium .

心脏被纤维囊（心包）完全包裹。

So, moving from the outside of the heart to the inside of the heart: after the epicardium, there's the myocardium, which is the muscular middle layer.

从心脏的外侧到心脏的内部：在心外膜后，有心肌层，即中间的肌肉层。

The inner layer is called the visceral layer, and it gets stuck tightly to the heart itself, forming the epicardium - or the outer layer of the heart.

而内层被称为脏层，它紧紧地贴合在心脏上，形成心外膜，即心脏外层。

Meanwhile, the inner serous pericardium consists of an inner visceral layer, or epicardium — which is actually part of the heart wall — and an outer parietal layer.

同时，内部浆液性心包由内部内脏层或心外膜——实际上是心壁的一部分——和外部顶层组成。

Whatever the case, the heart needs blood, and if we look at the heart wall, there's three layers—the outermost layer, the epicardium, then the myocardium in the middle, and the endocardium inside the heart.

无论什么情况下，心肌都需要供血，我们学习心壁时知道，心壁有3层：最外层的心外膜、中层的心肌，以及心脏内的心内膜。