What is the role of the synapse in neuronal transmission, and why is it important?

The synapse is a structure that permits a neuron to send an electrical or chemical signal to another neuron. It is where neurones can communicate with each other.

It contains a pre-synaptic and post-synaptic membrane, ensuring that transmission is unidirectional. This is important, as the nervous system likes to work in loops (e.g. when you put your hand on something hot). These loops would not work if messages were being sent in both directions.

The synapse plays a gatekeeper role. The need for vesicle exocytosis and receptor activation allows neurones to filter out low-level stimuli, and prevent stimulation (difference between putting your hand in a fire and putting your hand on a radiator) 

The synapse allows more than two neurones to meet and communicate with each other. This provides flexibility and integration, meaning the message being sent can be altered (e.g. fight or flight mode)