synaptic transmission

• synaptic transmission

  -passing a message from one neuron to another

  -chemical transmission

  -happens at the synapse
• the steps of synaptic transmission

  1. action potential (electric impulse) arrives at the pre-synaptic terminal.

  2. stimulates vesicles (hold neurotransmitters).

  3. releases neurotransmitters that diffuse in the synapse (between 2 neurons).

  4. neurotransmitters arrive at post-synaptic receptors.

  5. post-synaptic effectors are either excitatory or inhibitory.

  6. likelihood of postsynaptic neuron firing is determined by the neurotransmitters binding to the post-synaptic neuron.

  7. summation.

  -if neurons are not picked up in the synaptic cleft they are destroyed by enzymes.
• electric vs chemical

  -within neurons = electric

  -between neurons = chemical
• excitation vs inhibition

  Excitation: increase the positive charge of the postsynaptic neuron e.g., adrenaline. More likely to pass the electrical impulse.

  
  

  Inhibition: increase the negative charge of the postsynaptic neuron making it less likely that the electrical impulse will be passed e.g., serotonin.
• do neurotransmitters pass through to the next neuron?

  No. Neurotransmitters just bind to the receptors & present themselves - they do not pass through to the next neuron.
• summation

  The postsynaptic neuron firing is based on this. More excitation transmitters = more likely to fire; more inhibition transmitters = less likely to fire.