Synaptic Transmission

[blank_start]Neural groups[blank_end] are groups in which neurons communicate with each other. Signals [blank_start]within the neuron[blank_end] are transmitted electrically, but signals between neurons are transmitted by [blank_start]synaptic transmission[blank_end]. Each neuron is separated from the next one by a [blank_start]synapse[blank_end], the synaptic [blank_start]cleft[blank_end], the [blank_start]presynaptic[blank_end] terminal and the [blank_start]postsynaptic receptor[blank_end] site. When the electrical impulse reaches the presynaptic terminal it triggers the release of [blank_start]neurotransmitters[blank_end] from the [blank_start]synaptic vesicles[blank_end].

A neurotransmitter is [blank_start]a chemical[blank_end] that [blank_start]diffuses across the synapse[blank_end] to the [blank_start]next neuron in the chain[blank_end]

The [blank_start]neurotransmitter[blank_end] crosses the gap and is taken up by the [blank_start]postsynaptic receptor sites[blank_end], the chemical message is then converted back into an [blank_start]electrical impulse[blank_end] and the process of [blank_start]transmission[blank_end] begins again. Each [blank_start]neurotransmitter[blank_end] has its own specific [blank_start]molecular structure[blank_end] that fits into a [blank_start]postsynaptic receptor site[blank_end].

Summation is the process by which it is decided whether [blank_start]a postsynaptic neuron fire[blank_end]

The [blank_start]excitatory and inhibitory[blank_end] influences are [blank_start]summed[blank_end] and if the net effect on the [blank_start]postsynaptic neuron[blank_end] is inhibitory then it is [blank_start]less[blank_end] likely to fire, but if the net effect is exhibitory it is [blank_start]more[blank_end] likely to fire

Serotonin causes [blank_start]inhibition[blank_end] in neighbouring [blank_start]neurons[blank_end], meaning the neuron becomes more [blank_start]negatively charged[blank_end] and [blank_start]less[blank_end] likely to fire

Adrenaline causes [blank_start]excitation[blank_end] of the [blank_start]postsynaptic neuron[blank_end] by increasing its [blank_start]positive charge[blank_end] and making it [blank_start]more[blank_end] likely to fire