SYNAPTIC TRANSMISSION

• SYNAPTIC TRANSMISSION


  At the terminal buttons of a neuron synaptic transmission takes place
• STEP 1


  An action potential reaches the presynaptic neuron which causes vesicles(sacs filled with NT) to fuse with the membrane
• STEP 2


  NT are released into synapse and travel across by diffusion where they can bind to receptors on the post synaptic neuron
• STEP 3


  Each NT will have a specific receptor for its shape(lock and key hypotheses)
• STEP 4


  What happens at the post synaptic neuron depends on whether the NT'S are inhibitory or excitatory. Neurons receive both excitatory post-synaptic and inhibitory post-synaptic potential at the same time
• STEP 5


  The likelihood of the cell firing is therefore determined by adding up the excitatory and inhibitory synaptic input. The net result (summation) determines whether or not the cell fires
• WHY DO NEURONS ONLY TRANSMIT IN ONE DIRECTION

  The synaptic vesicles containing the NT are only present on/ released from the presynaptic neuron

  The receptors for NT are only on the post synaptic membrane

  It is the binding of the NT to the receptor that enables the information to be transmitted to the next neuron

  Diffusion of the neuron means they can only go from high to low concentration(presynaptic to post synaptic)