Synaptic Transmission Flashcards
(14 cards)
What is the pre-synaptic neuron?
The neuron that transfers the action potential
What is the post-synaptic neuron?
The neuron that receives the action potential
What happens during exocytosis?
- the action potential reaches the pre-synaptic terminal
- this triggers the release of neurotransmitters from vesicles on the pre-synaptic membrane
Describe synaptic transmission.
- exocytosis occurs
- neurotransmitters diffuse across the synaptic cleft
- they bind to post-synaptic receptor sites
How long does synaptic transmission take?
A fraction of a second
Define re-uptake.
The effects of synaptic transmission are terminated
What occurs during re-uptake?
- the neurotransmitter is taken back by the vesicles on the pre-synaptic membrane
- they are stored for later release
What are excitatory neurotransmitters?
- cause an electrical charge in the post-synaptic neuron
- results in an excitatory post-synaptic potential (EPSP)
- post-synaptic neuron is more likely to fire an impulse
What are inhibitory neurotransmitters?
- cause an inhibitory post-synaptic potential (IPSP)
- post-synaptic neuron is less likely to fire an impulse
Define summation.
The net calculation of excitatory and inhibitory synaptic input.
What does summation mean?
- if it is inhibitory the neuron won’t fire
- if it is excitatory the neuron will fire
Why can synaptic transmission only travel in one direction?
- vesicles containing neurotransmitters are only present on the pre-synaptic membrane
- receptors are only present on post-synaptic membrane
- information can only be passed if neurotransmitter binds to the receptor
- neurotransmitters travel via diffusion (high to low) from pre to post synaptic membrane
Give an example of a medication that affects neurotransmissions.
Psychotic drugs such as SSRIs
- they affect transmission of neurotransmitters across the synapse
How does pain medication work?
- they mimic the effects of inhibitory neurotransmitters
- affects summation
- action potential is inhibited
