3- synaptic transmission Flashcards
1
Q
explain the process of synaptic transmission
A
- neuron transmits an action potential
- action potential reaches the pre-synaptic terminal
- triggers release of neurotransmitters from vesicles on pre-synaptic membrane via exocytosis
- neurotransmitters diffuse across the synaptic cleft
- bind to post-synaptic receptor sites
- post synaptic neuron more likely to fire impulse if excitatory and less likely to fire impulse if inhibitory
- neurotransmitter taken back by vesicles on pre-synaptic membrane via re-uptake
2
Q
what is re-uptake
A
- neurotransmitter taken back by vesicles on pre-synaptic membrane where stored for later release
- the quicker it is taken back, the shorter the effects
3
Q
why can information only travel in one direction at a synapse
A
- vesicles with neurotransmitters are only present on pre-synaptic membrane
- receptors only present on post-synaptic membrane
- binding causes info to be transmitted
- diffusion of neurotransmitters can only happen from high–> low conc so only travel from pre-synaptic–>post-synaptic membrane
4
Q
what are psychoactive drugs and how do they work
A
- medication that affects brain function to alter perception, mood or behaviour
- e.g. SSRIs
- work by affecting (increasing/inhibiting) transmission of neurotransmitters across the synapse
5
Q
which neurotransmitter is only inhibitory
A
GABA
6
Q
describe excitatory neurotransmitters
A
- cause electrical charge in post-synaptic membrane resulting in an excitatory post-synaptic potential (EPSP)
- cell is more likely to fire an impulse
7
Q
describe inhibitory neurotransmitters
A
- cause electrical charge in post-synaptic membrane resulting in an inhibitory post-synaptic potential (IPSP)
- cell is less likely to fire an impulse
8
Q
what is summation
A
- neuron recieven both EPSPs and IPSPs
- likelihood if the cell will fire is determined by adding up the excitatory and the inhibitory synaptic input
- more IPSPs=less likely to fire
- more EPSPs=more likely to fire
