And those fast, leaky cells are found in the sinoatrial node, or the SA node, up in the right atria.

这些快速渗漏的细胞房结，或 SA 结，右心房上方。

This means that the SA node essentially skips one cycle of sending its own signal.

这意味着房结跳过了发放它自己冲动的一个周期。

Notice that each time the SA node fires, it resets all the slower ones, and this is exactly how it works.

注意每次房结放电，它重置了所有更慢的细胞，这是它工作的原理。

Since the sinus node's going at 1 second per beat, and it's out of refractory, it fires off a signal and the atria contracts and you get another P wave, which is right on schedule.

由房结以1秒/搏的速率工作，且处不应期之外，它发放一个信号，心房收缩，你看到了另一个P波，这完全在节律之中。

So the sinus node waits the same interval but fires based on the ectopic beat.

接下来房结又等待了同样的间隔时间，该时间内传导的冲动是基异心搏发出的。

Now both relax and come out of refractory, and exactly one second later, the sinus node sends another signal and the atrium contracts as it should, and then everything carries on as per usual.

现在心房心室均舒张、处不应期之外，恰好一秒钟以后，房结发放了另一个冲动，心房按照既定收缩，然后一切按照行。

Now, though, let's say you have a ventricular ectopic focus somewhere in the ventricles, which is a cell or area of tissue that sends off an early depolarization wave, before even the SA node gets to fire.

现在假设你在心室某处有一个异起搏点，是一个发放提前除极波的细胞或组织区域，甚至在房结开始放电之前。

Now, if we measure out the interval between each SA node fire, we see that it should have fired here, but it doesn't because it was depolarized by the ectopic focus.

这时，如果我们测量每一个房结冲动的间隔，我们可以看到它本应在此处发放，但并没有，因为它被异起搏点除极化了。

In this case, after being depolarized, the sinus node waits its 1 second, and then sends another signal and again we carry on as normal.

在这种情况下，房结在除极之后等待了1秒，然后发放另一个信号，心搏得以重新行。

The gene caused the creation of an exact copy of the sino-atrial node in the heart's upper right chamber.

该基因导致心脏右上腔室中房结的精确副本的产生。

The starting point of the intrinsic conduction system is the sinoatrial node, or SA node.

内在传导系统的起点是房结。

Heart blocks are classified by location where the blockage occurs: - SA nodal block, or SA block – blockage within the SA node.

-房结结阻滞，或房阻滞--房结内的阻滞。

One important effect of the premature depolarization is that the ectopic focus will depolarize the cells of the SA node, causing the SA node to skip a cycle.

过早除极的一个重要影响是异起搏点将会使房结细胞除极，导致房结跳过一个心动周期。

In fact, if something goes wrong with this node, a person might need to have an artificial pacemaker implanted to keep their heart's steady beat.

事实上，如果房结出了问题，个体可能需要植入人工心脏起搏器来保持心脏的稳定跳动。

When the atria are full of blood, the SA node fires, electrical signals spread throughout the atria and cause them to depolarize.

心房充盈时，房结立即发出冲动，电信号会传遍整个心房并使其去极化。

So let's say the SA node is firing along as usual, but all the sudden an ectopic focus fires one off early.

比方说房结和往一样发放冲动，但是一个异起搏点提前发放冲动阻断了这些冲动的传播。

Now, the interesting thing is that in addition to the pacemaker cells in the SA node, cells in the AV node, Bundle of His, and the Purkinje fibers, all have the ability to generate an electrical potential.

好了，有趣的是除房结起搏细胞以外，房室结、希氏束以及浦肯野纤维中的细胞都有形成电势的能力。

In a healthy heart, the sinoatrial node or SA node initiates all electrical impulses in the atria.

在健康的心脏内，房结（SA结）产生心房内的所有电脉冲。

Electrical impulses from the SA node spread throughout both atria and stimulate them to contract.

房结发出的电脉冲扩散到整个心房并刺激它们收缩。

In this case the wave of depolarization makes it into the atrium and depolarizes the atrium, including the sinus node, so essentially the sinus node resets about 4.4 boxes from the last, or 0.88 seconds.

在这种情况下，除极波入心房并使其除极，包括房结，因此房结被重置，离上次大约4.4小格，或0.88秒。