Synapses
| English | Chinese | Pinyin |
|---|---|---|
| synapse | 突触 | tū chù |
| neurotransmitter | 神经递质 | shén jīng dì zhì |
The gaps between neurones
- Neurones don't quite touch — there's a tiny gap between them called a synapse 突触.
- How the signal crosses this gap is clever chemistry.
A synapse is:
A synapse is the junction between neurones.
An impulse cannot jump the synapse directly, so it is carried by ______ chemicals.
Neurotransmitters carry the signal across.
What a synapse is
- A synapse is the junction between two neurones.
- The electrical impulse cannot jump the gap directly.
At a synapse, neurotransmitter 神经递质 diffuses across the gap, so impulses travel one way only
Across the synapse
Neurons don't touch — the impulse crosses the tiny gap using a chemical messenger.
The signal crosses a synapse as:
Neurotransmitters diffuse across the gap.
Neurotransmitters move across the synapse by:
They diffuse across the small gap.
Crossing the gap
- The impulse triggers the release of neurotransmitter chemicals.
- These diffuse across the gap and trigger a new impulse in the next neurone.
Synapses allow impulses to travel in one direction only.
Neurotransmitter is released on one side only.
One-way only
- Neurotransmitters are released on one side only, so signals cross a synapse in one direction.
- This keeps impulses travelling the right way through the nervous system.
Worked example. An impulse reaches the end of a neurone, releasing neurotransmitter into the synapse. It diffuses across, binds to the next neurone, and starts a fresh impulse — converting electrical → chemical → electrical.
You've got it
- a synapse is the gap between two neurones
- the signal crosses as neurotransmitter chemicals that diffuse across
- synapses transmit in one direction only