They're small molecules that - whose principal function in the body is to carry signals from one cell in the nervous system to another.

它们都是小分子,在体内主要功能是在,神经系统内将信号,从一个细胞传导到另一个细胞

耶鲁公开课 - 生物医学工程探索课程节选

Well, what happens when the signal gets to the end of the axon?

那当信号传导至轴突末端后又会发生什么

耶鲁公开课 - 生物医学工程探索课程节选

That's what makes proteins useful in transmitting or responding to signals.

它们能够传导信号,或者反馈信号

耶鲁公开课 - 生物医学工程探索课程节选