Synaptic Signalling Flashcards
What occurs at the presynaptic active zone?
- vesidue docking
- exocytosis
What occurs at the postsynaptic density.
- receptorexpression
- machinery for intra-cellular signalling
What is an axodendritic neurone?
When the axon makes contact with the cell body of another neurone
What is an axosomatic neurone?
When the axon connect to the cell body of another neurone
more powerful
What is an axoaxonic neurone?
When the axon attaches to the axon of another neurone
How does the point of synaptic contact affect the likelihood of an action potential forming?
-closer to axon hillock-greater influence on action potential generation
Where are inhibitory synapses often found?
on soma (cell body) and near axon hillock because these are the best places to control neurone excitability
Why might axondendritic input not spread down dendrite to effect soma/axon hillock?
- if voltage dependent channels expressed on dendrites can’t amplify excitatory input
- some dendrites don’t have channels
- only passive spread of depolarisation
- therefore large input required
How does an inhibitory ionotropic receptor work?
-When neurotransmitter binds, chloride ions. enter making membrane potential more negative, making it less likely for an action potential to occur (hyper polarisation)
Which is faster ionotropic or metatropic?
Ionotropic
What is longer-lasting?
metatropic
In metatropic pathway, where is the G protein found?
on the intracellular side of membrane
After the G protein coupled receptor is activated, what happens?
- open or close ion channels
- stimulate or inhibit enzymes/secondary messenger systems
What is spatial summation?
summing of post synaptic potentials generated at separate synapses
What is temporal summation?
summing of post synaptic potentials generated at the same synapse, of they occur in rapid succession
