translation.en: Every beat of your heart depends on this crucial region, the sinoatrial node, which has about 10,000 independent cells that would each beep, have an electrical rhythm -- a voltage up and down -- to send a signal to the ventricles to pump.
translation.zh: 心脏的每一次跳动都取决于这个关键的部位，窦房结， 大约一万个相互独立的细胞 以一种电流的韵律——电压起伏——“鸣叫”。 以此来发出让心室运作的信号。