Synaptic transmission

• What is a synapse?


  The gap between two neurons where neurotransmitters diffuse across when an electrical impulse reaches the end of the presynaptic neuron
• What are neurotransmitters?

  Chemicals that diffuse across the synapse which then reach the postsynaptic receptor site where the chemical message is converted back into an electrical impulse
• inhibition:

  Neurotransmitters like serotonin cause inhibition in the receiving neuron resulting in the neuron becoming more negatively charged and less likely to fire
• Excitation:

  Neurotransmitters like adrenaline cause excitation of the postsynaptic neuron by increasing its positive charge making it more likely to fire
• Summation:

  Whether a postsynaptic neuron fires is decided by the process of summation

  • The excitatory and inhibitory influences are summed
  • If the net effect on the postsynaptic neuron is inhibitory then it is less likely to fire
  • If the net effect is excitatory then it is more likely to fire
  • Action potential is only fired if the sum reaches the threshold