Synapses
The gap between neurones (Supplement)
- A synapse is a junction (a tiny gap) between two neurones.
- One side holds vesicles of neurotransmitter.
- The other side has receptor proteins.
Practice
A synapse is:
A synapse is the junction between two neurones, with a small gap between them.
What happens at a synapse
- an impulse arrives and makes the vesicles release neurotransmitter into the gap.
- the neurotransmitter diffuses across the synaptic gap.
- it binds to receptor proteins on the next neurone.
- this starts a new impulse in that neurone.
- Because only one side releases the chemical, impulses travel in one direction only.
Practice
How does the signal cross the synaptic gap?
Neurotransmitter is released, diffuses across the gap and binds to receptors, starting a new impulse.
Practice
Synapses make nerve impulses travel in one direction only.
Only one side releases neurotransmitter, so impulses can pass one way only.
You've got it
Key idea
- a synapse is a tiny gap between two neurones (Supplement)
- neurotransmitter is released, diffuses across, and binds to receptor proteins, starting a new impulse
- synapses make impulses travel one way only