Explain how neurons communicate across a synapse.
- A neuronal action potential depolarises the pre-synaptic membrane (neuron 1) causing voltage-gated calcium channels to open.2) Extracellular calcium ions bind to receptors on the pre-synaptic membrane causing vesicles containing a neurotransmitter to move towards the membrane in the process of exocytosis.3) The vesicles fuse with the membrane and the neurotransitters are deposited in the synaptic cleft.4) The neurotransmitter molecules diffuse across the synaptic cleft and bind to their complimentary receptors on the post-synaptic membrane (neuron 2).5) Sodium ion channels on the post-synaptic membrane open, causing the membrane to depolarise and initiating an action potential down the neuronal membrane.
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