Synaptic Transmission Flashcards
What is a synapse?
Site of communication between a neuron and some other cell
What is the presynaptic cell?
The presynaptic cell releases neurotransmitters across the synaptic cleft to the postsynaptic cell
What is the postsynaptic cell?
A cell that receives signals from a neuron across a synapse, interpreting neurotransmitters and potentially generating its own response
What are electrical synapses?
When pre and postsynaptic membranes are locked together
Where can electrical synapses be found?
Eye
What are chemical synapses?
Cells not directly coupled so they use neurotransmitters
What are excitatory neurotransmitters?
Cause depolarisation (more positive potential)
What are inhibitory neurtotransmitters?
Cause hyperpolaristaion (more negative potential)
Where are small neurotransmitters synthesised and packaged?
In the synaptic terminal
Where are peptide neurotransmitters synthesised and packaged?
In the cell body and then transported to the synaptic terminals
What are the two main types of neurotransmitter receptors?
Ligand gated ion channels and G protein coupled receptors
What are g protein coupled receptors?
Ion channel which relies on an intermediary second messenger to open hence results in a slow response
How is action terminated?
When the neurotransmitter is broken down, taken up or diffused away
What are the synapsis which release acetylcholine called?
Cholinergic
What are the two types of receptors for acetylcholine?
Nicotinic - ligan gated
Muscarinic - G protein coupled
What is acetylcholinestrase?
Enzyme which breaks down acetylcholine into acetate and choline
What triggers the release of acetylcholine?
Calcium ions entering the cytiplasm
What does acetylcholine do when released?
Binds to sodium channel receptors on the postsynaptic membrane producing a graded depolarisation
What happens after acetylcholine binds to sodium channels?
Net entry of Na+ initiates a muscle action potential
