Key terms for this topic:
Neurotransmitter: (transmitter substance) chemical that diffuses across the cleft of the synapse to transmit a signal to the postsynaptic neurone.
Cholinergic synapses: those that use acetylcholine as their transmitter substance
Synaptic knob: swelling at the end of the presynaptic neurone.
Acetylcholinesterase: enzyme in synaptic cleft. breaks down the transmitter substance acetylcholine.
Structure of a cholinergic synapse:
A synapse is a junction between one or more neurones, it is where one neurone can communicate with, or signal to, another neurone.
- the synaptic cleft (small gap between two neurones) is 20nm wide
- the action potential produced by movements of ions accross neurone membrane
- note, the action potential cannot bridge the gap between two neurones, the presynaptic action potential causes release of the transmitter substance that diffuses across the gap and generates a new action potential in postsynaptic neurone.
- synapses that use acetylcholine as the neurotransmitter are called cholinergic synapses.
The synaptic Knob contains a number of specialised features: