Describe the steps following the arrival of an action potential to the pre-synaptic bulb allowing for transmission of a signal across a synapse.
Depolarisation of plasma membrane opens voltage-gated calcium channels, allowing calcium ions to move into pre-synaptic bulb down the concentration gradientHigh intracellular calcium results in the mobilisation of neurotransmitter-containing vesicles to fuse to the pre-synaptic membrane and release the neurotransmitter via exocytosisNeurotransmitter diffuses across the synaptic cleft and binds to cell surface receptors on the post-synaptic membrane which activates the receptors, causing them to open a channel, allowing sodium ions into the post-synaptic bulbIf sufficient receptors are activated and sufficient sodium is released into the post-synaptic neuron, the membrane will become depolarised and the transmission of the action potential can continue
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