Note that this simple synapse art will be repeated throughout this activity, with the relevant portion circled in blue, to help you keep track of where we are as we zoom in on the various processes of the action at the synapse.
To review the structure of the synapse, click on a label to highlight the part of the diagram to which the label is pointing.
Most communication within our nervous system is the result of neurons, the basic, single-cell units of our nervous system (also called nerve cells), firing messages off to each other at the synapse. The synapse is the place where the axon of one neuron contacts the dendrite or cell body (soma) of the next neuron. The sending neuron is called the presynaptic neuron, and the receiving neuron is called the postsynaptic neuron. The firing response, called the action potential, is an electrical message that travels down the axon of the presynaptic neuron to the axon terminal, where it stimulates the release of stored neurotransmitters into the synaptic cleft. These neurotransmitters bind at receptor sites on the postsynaptic neuron and influence whether this receiving neuron will in turn fire an action potential of its own. All this happens in milliseconds!
