Module 3: Synaptic transmission Flashcards
what is temporal summation?
when 2 EPSPs from the same presynaptic neuron occur close in time to depolarise the membrane to threshold
what is spatial summation?
2 EPSP from different presynaptic neurons occur close in time to depolarise the membrane threshold
what’s the difference between temporal and spatial summation?
temporal: EPSP from same presynaptic neuron
Spatial: EPSP from 2 different presynaptic neurons
where does a synapse occur?
At the end of the axon - presynaptic neuron/axon terminal - and post synaptic neuron (attached to other neuron area)
where can synapses form on a neuron?
cell body: axosomatic
dendrite:axodendritic
hillock:axoaxonal synapse
which neuron to neuron synapse is most common?
axon-dendrite (axodendritic)
what is the name for the chemicals in the vesicles of the presynaptic neuron/axon terminal?
neurotransmitters
are neurotransmitter chemical or electrical?
chemical
what is the name of the gap between the presynaptic terminal and postsynaptic terminal?
the synaptic cleft
how do the receptor proteins work in the postsynaptic terminal?
the neurotransmitters chemically bond to the protein receptors, opening them
how do the electrical signals from the axon terminal convert into a chemical signal?
the voltage from the action potential triggers the +Ca2 voltage gated protein to open, flooding the presynaptic terminal and causing the vesciles to exocytosis to the membrane wall.
what happens when the neurotransmitters are in the synapse cleft?
the neurotransmitters bond to the ligand or g couple protein gates and cause them to open, allowing Na+,K+ and Cl- to flow bidirectionally across the postsynaptic membrane generating a local or graded potential
why is it useful to have many electrical transmitters happening?
allows to modification of the signal
what is a ligand gated ion channel?
a channel that is activated by chemicals (neurotransmitters) which allow ions to flow through and cause a direct change in the EPSP or IPSP
what does the ligand gate do?
creates a small and direct change in the voltage to create a local or graded potential