Action potential and synaptic transmission

• Action potential - neuron stimulated to release neurotransmitters - response of postsynaptic neuron if threshold reached - sends electrical impulse along neuron
• Excitatory neurotransmitter causes axon to become less negative = increases likelihood of action potential firing
• Inhibitory neurotransmitters - cause axon to become more negative = decrease likelihood of action potential firing
• Synaptic transmission - specific neurotransmitters can only fit into specific receptors on postsynaptic neurone
• Synaptic transmission - AP reaches end of presynaptic neurone vesicle fuse with the presynaptic membrane. Neurotransmitter diffuse across synaptic cleft and bind to receptors on postsynaptic neurone. Chemical signal is converted back to an electrical signal.
• Neurotransmitter molecules that are not absorbed will be destroyed by enzyme in synaptic cleft or reabsorbed into presynaptic neurone called reuptake via an uptake pump ( neurotransmitter can be used again )