Synaptic signalling Flashcards
What is an axodendritic neurone?
When the axon makes contact with the dendrite of another neurone
What is an axosomatic Neurone?
When the axon connect to the cell body of another neurone (this is more influential and often inhibitory)
What is an axoaxonic neurone?
When the axon attaches to the axon of another neurone
Where will an action potential only activate at?
At the axon hillock
What influence does the point of synaptic contact have?
Closer to the axon hillock - greater the influence on action potential generation
Inhibitory synapses often found on soma near the axon hillock
Best positioned to control neurone excitability
What is the excitatory effect of a ligand binding to an ionotropic receptor?
Neurotransmitter binds
causes Na channels to open
Leads to Na influx due to electrochemical gradient driving ion movement
May generate an EPSP/IPSP
What is the inhibitory effect of a ligand binding to an ionotropic receptor?
Neurotransmitter binds
Causes Cl channels to open
Leads to Cl influx and the membrane becomes more negative
No action potential is generated
What do varying subtypes of receptors allow for?
Both fast and slow transmission at the same synapse
What is spatial summation?
Summing of post synaptic potentials generated at separate synapses to overcome threshold.
What is inhibitory spatial summation?
Where an EPSP and IPSP are of the same magnitude and therefore will have no change in the memrbane potential
What is temporal summation?
Summing of post synaptic potentials generated at the same synapse
What occurs at the presynaptic active zone?
Vesicle docking
Exocytosis
What occurs at the postsynaptic density.
- receptor expression
- machinery for intra-cellular signalling
Where are inhibitory synapses often found?
on soma (cell body) and near axon hillock because these are the best places to control neurone excitability
Which receptor response is faster ionotropic or metatropic?
Ionotropic
