which separates the atria from the ventricles.

即将心室与心房分开的房室隔
The heart is kind of tilted to one side,

心脏是向一侧倾斜的
it's not straight up and down,

并不是垂直上下的
so the atria are up here and the ventricles are down here,

心房在上方心室在下方
there's a septum in between and that's where this AV node sits.

中间是房室隔那就是房室结的所在
It turns out that this septum is electrically insulating

房室结是绝缘的
and so if a action potential--

因此如果动作电位--
a wave of action potential gets generated up in the atrium,

从心房发出的动作电位
it stops when it hits the septum,

在到达房间隔时终止
it doesn't move directly to the ventricles.

并不是直接传至心室
The muscles of the atrium

心房的肌肉
and the muscles of the ventricle are electrically isolated.

和心室的肌肉在电传导上相互是独立的