Flashcards in Neuromuscular junction Deck (20):
What is a neuromuscular junction?
A specialised synapse between a motor neurone and muscle cell
How is different to a normal synapse?
The post synaptic cell is a muscle cell
What does it trigger?
What is it specialised to do?
Rapid reliable neurotransmission
Where does the motor neurone terminate?
At the motor end-plate
What specialisation can be seen at the post synaptic membrane?
Lots of folds
Meaning lots of receptors
What neurotransmitter is used?
What is synaptotagmin?
A sensor of Ca2+ levels
Triggers movement of vesicles
Vesicle fuses with membrane
What receptors are present in neuromuscular junctions?
Nicotinic acetylcholine receptors
What kind of channels are receptors?
What happens after ACh binds to the ACh receptor?
The channel opens
It is permeable to Na+ and K+
What is the Em of the muscle cell?
What is the ion movement in the cell?
More Na+ influx than there is K+ efflux
Describe the driving force on Na+ and K+
Na+ is great
K+ is very small
What is the end-plate potential?
What determines end-plate potential?
-20mV is the potential after the release of neurotransmitter
What does the end-plate potential initiate?
An action potential in the muscle
What is the difference between the end-plate potential and the action potential?
The end-plate potential decays
Decreases as distance from motor end-plate increases
The action potential does not
What is the delay between a presynaptic action potential and an end-plate potential?