Synaptic transmission

• The process of synaptic transmission

  1. action potential received at presynaptic neurone
  2. Vesicles move towards the membrane
  3. Membrane of vesicles will fuse with the membrane of the neurone
  4. Neurotransmitters diffuse across the synapse till it reaches the receptor site
  5. Neurotransmitters bind to the receptor site
  6. this creates an action potential at the post synaptic receptor site
• Excitatory neurotransmitters 


  • Acetylcholine and noradrenaline

  The release of excitatory neurotransmitters mean the neurone develops an excitatory post-synaptic potential, which means it will be more likely to fire with an excitatory impulse and produces a positive charge within the cell
• Inhibitory neurotransmitter 


  • serotonin and GABA

  An inhibitory neurotransmitter means the neurone develops an inhibitory post-synaptic potential generating a negative charge within the cell and so are less likely to fire
• Summation 


  A nerve cell can receive both excitatory and inhibitory post-synaptic potentials at the same time. the sim of each is what decides whether a cell fires or not.

  The strength of the excitatory post-synaptic potentials (EPSP) can be calculated in two ways. Spatial summation ( where there are many different EPSP’S occurring on different locations in the same post-synaptic neurone). Temporal summation is where a large number of EPSP’s are creates on the same synapse but by a high frequency of firing. if the EPSP’s are more active then the cell will fire, if not then it will not fire