Synaptic transmission Flashcards
Explain the difference between excitatory and inhibitory postsynaptic potentials Define spatial and temporal summation Describe presynaptic inhibition Define 3 different classes of neurotransmitter molecules and examples Describe acetylcholine lifecycle at the neuromuscular junction
What is the junction between one nerve and another nerve?
Synapse junction
What is the junction between nerve and a skeletal muscle?
Neuromuscular junction
Describe the 6 events at a junction when an action potential is received:
- AP depolarises terminal
- Voltage gated Ca ion channels open and Ca enters
- Vesicles then fuse with the membrane
- Neurotransmitter is released by exocytosis and then diffuses
- Binds to receptor and activates it
- Re-uptake of the molecules from vesicle
What is it called when a neurotransmitter binds to a receptor?
Postsynaptic response
What is the response for an action potential to occur?
All or nothing
Where are nicotinic receptors found?
On the postsynaptic membrane of a neuromuscular junction
What happens when an excitatory post synaptic potential occurs? (4)
The ACh binds to the nicotinic receptor
Receptor changes shape
Na ion channel is opened
Depolarisation to -55
What happens when an inhibitory postsynaptic potential occurs? (4)
Inhibitory neurotransmitter (GABA)
Chloride ions enter
Cell made more negative
Local hyper polarisation
What is spatial summation?
2 EPSPs on adjacent membrane add together
What is temporal summation?
2 EPSPs close in time can add together
Name 3 neurotransmitters
Amino acids, classical neurotransmitters and neuropeptides
Name 2 examples of an amino acid neurotransmitter:
Glycine and GABA
Name 2 examples of classical neurotransmitters:
Noradrenaline, ACh
Name 2 examples of a neuropeptide:
TRH and substance P
Where do postsynaptic potentials occur in the CNS
Dendrites and cell body
