Explain the mechanism of synaptic transmission.

Synapses are the physical gaps that separate neurons from other cells. Neurons transmit information across synapses by converting the electrical signal into a chemical signal, usually neurotransmitters. These neurotransmitters are sent across the synaptic cleft, they bind to receptors on the post-synaptic membrane, and can trigger a variety of responses on this cell. When an action potential reaches the axon terminal at the pre-synaptic neuron, it triggers the opening of voltage-gated Calcium (Ca2+) channels. Ca2+ ions diffuse into the cell, and promote the fusion of transmitter-containing vesicles with the pre-synaptic membrane. The vesicles 'dock' with the membrane, causing the neurotransmitter to be released into the synaptic cleft via exocytosis, and diffuses across the gap to bind to the post-synaptic membrane. The binding of transmitter to the post-synaptic membrane causes a signal to be initiated in the post-synaptic cell, thus an action potential is triggered and propagated along this neuron.