What occurs when the nerve impulse reaches the terminal of the neuron? How is the signal continued. These are the questions to be discussed today. Define and discuss pre synaptic and post synaptic neurons, neurotransmitters, where and why they are produced. The effect on the post synaptic neuron of the chemical neurotransmitters to cause the next neuron to fire. Differentiate between excitatory and inhibitory impulses, inactivators and uptake inhibitors.