Nerve Junctions

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Nerve junctions

Neurotransmitter - A neurotransmitter is a chemical which diffuses across the synaptic cleft to trigger an action potential inthe postsynaptic neurone.

Cholinergic Synapse - A cholinergic synapse is a type of synapse which uses acetylcholine as the neurotransmitter.

Synaptic Knob - The synpatic knob is a swelling located at the end of a neurone.

Structure of a cholinergic synapse

A synapse is a junction between two or more synapses. The space between the two neurones is known as the synaptic cleft.Action potentials are unable to cross the synaptic cleft. Therefore, a neurotransmitter substance diffuses across the synaptic cleft instead and binds to receptors on the postsynaptic neurone. The neurotransmitter used in cholinergic synapses is known as Acetylcholine.

The Synaptic Knob

The ending of a presynaptic neurone consists of a swelling known as the synaptic knob. The synaptic knob has a number of specialised features.


The postsynaptic membrane

The postsynaptic membrane has specialised sodium ion channels. These specialised sodium ion channels consist of five polypeptide subunits. Two of these polypeptide subunits are receptor sites


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