Axon
Some are chemical, others are electrical. Electrical synapses send an ion current flowing directly from the cytoplasm of one nerve cell to another through small windows called gap junctions which causes all nearby synapses and neurons to be activated all together which is useful in places like your heart. Chemical synapses use neurotransmitters to communicate by diffusion through a synaptic gap. Presynaptic neuron sends signals through presynaptic terminals filled with synaptic vesicles filled with the neurotransmitters. Postsynaptic neurons make the neurotransmitters in the receptor region on the dendrite or cell body.