This set-up has two principal parts: The cell that's sending the signal is the presynaptic neuron, and it transmits through a knoblike structure called the presynaptic terminal, usually the axon terminal.

这种设置有两个主要部分：发送信号的细胞是突触前神经元，它通过一个叫做突触前终端的节状结构进行传输，通常是轴突终端。