Synaptic transmission is the process in which a nerve impulse (action potential) passes across the synaptic gap from the presynaptic neuron to the post-synaptic neuron.

Information is passed down the axon of the neuron as an electrical impulse known as an action potential. Once the action potential reaches the end of the axon it must cross over the synaptic gap. At the end of the neuron (in the axon terminal) are the synaptic vesicles which contain chemical messengers, known as neurotransmitters. When the electrical impulse (action potential) reaches these synaptic vesicles, they release their contents of neurotransmitters. Neurotransmitters then carry the signal across the synaptic gap. They bind to receptor sites on the post-synaptic cell that then become activated. Once the receptors have been activated, they either produce excitatory or inhibitory effects on the post-synaptic cell, making the post-synaptic cell more or less likely to fire.

Please Note: These answers have been produced without the knowledge of the mark scheme and merely reflect my attempt at producing a model answer on the day of the exam.