Neuromuscular junction Flashcards Preview

Foundations of Neuroscience > Neuromuscular junction > Flashcards

Flashcards in Neuromuscular junction Deck (20):
1

What is a neuromuscular junction?

A specialised synapse between a motor neurone and muscle cell

2

How is different to a normal synapse?

The post synaptic cell is a muscle cell

3

What does it trigger?

Muscle contraction

4

What is it specialised to do?

Rapid reliable neurotransmission

5

Where does the motor neurone terminate?

At the motor end-plate

6

What specialisation can be seen at the post synaptic membrane?

Lots of folds
Meaning lots of receptors

7

What neurotransmitter is used?

Acetylcholine

8

What is synaptotagmin?

A sensor of Ca2+ levels
Triggers movement of vesicles
Vesicle fuses with membrane

9

What receptors are present in neuromuscular junctions?

Nicotinic acetylcholine receptors

10

What kind of channels are receptors?

Ligand-gated channels

11

What happens after ACh binds to the ACh receptor?

The channel opens
It is permeable to Na+ and K+

12

What is the Em of the muscle cell?

-90mV

13

What is the ion movement in the cell?

More Na+ influx than there is K+ efflux

14

Describe the driving force on Na+ and K+

Na+ is great
K+ is very small

15

What is the end-plate potential?

-20mV

16

What determines end-plate potential?

-20mV is the potential after the release of neurotransmitter

17

What does the end-plate potential initiate?

An action potential in the muscle

18

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

19

What is the delay between a presynaptic action potential and an end-plate potential?

1msec

20

Comment on the size of an end-plate potential, why?

It is a very large synaptic potential
High density of receptors
Large release of neurotransmitter