Synaptic Transmission

• Synaptic Transmission

  1. Neurotransmitters released from pre-synaptic neuron into synaptic cleft

  2. Neurotransmitters bind to receptor sites on post-synaptic neuron's dendrites
• Neurotransmitters


  Chemical messengers released by neurons
• Excitatory neurotransmitters


  • Make it more likely for action potential to be developed in postsynaptic cell
• Inhibitory neurotransmitters


  • Make it less likely for action potential to be developed in postsynaptic cell
• Action potential


  Electric message
• Synaptic Transmission steps

  1. Action potential travels down presynaptic neuron axon

  2. Synaptic vesicles merge/fuse with presynaptic cell membrane and release neurotransmitters into synaptic cleft

  3. Postsynaptic neuron receptors on dendrite membrane detect neurotransmitters

  4. If postsynaptic neuron passes a threshold = new action potential and passes message on

  5. Neurotransmitters detach from receptors for the reuptake process - transport proteins returning them to the presynaptic cell
• Excitation


  Increased likelihood of new action potential formation in postsynaptic cell; become depolarised when excitatory neurotransmitters detected by receptors - electrical charge becomes more positive and likely to fire
• Hyperpolarised


  Opposite of excitation, when inhibited neurotransmitters are detected