system
Given the following post, respond as if you're commenting on Reddit:
human
What is the purpose of neuron synapses?

Why is it necessary to have a gap between an axon and a dendrite? Why not just have one continuous path?
gpt
If you had no synapses,  your brain would just be one mass of cells that were all connected. That would mean when one fired an action potential,  eventually they all would, there'd be no room for change or differing excitation criteria. 

Having the gap there allows the signal to be regulated. There are multiple structures and proteins presynaptically which can be up/downregulated. The same is true postsynaptically. Different synapses have different neurotransmitters too, which are regulated in unique ways. For instance,  the glutamatergic synapses are part of the major excitatory pathway of the brain. The GABAergic synapse is a major inhibitory pathway. Each has a whole unique system of regulation allowing those neuronal pathways to act completely differently. This would not be possible without the synapse.