How does the signal jump across the synaptic gap?
The process of synaptic transmission involves the release of neurotransmitter molecules
that float across the synaptic gap and stimulate receptors in the next neuron.
Let’s enlarge a synapse to take a closer look at this process.
The axon terminal contains tiny sacs called synaptic vesicles.
These sacs are filled with special chemicals known as neurotransmitters.
When the neural impulse reaches the axon terminal,
the vesicles open up and release their neurotransmitter molecules into the synaptic gap.
The neurotransmitter molecules float across the gap,
and find their way to special receptors on the surface of the other neuron's membrane.
Here's a close up view of neurotransmitter molecules being released into the synaptic gap.
Each neurotransmitter molecule is like a piece of a jigsaw puzzle.
Each receptor or binding site will accept only a certain type of neurotransmitter.
If the puzzle piece fits and the neurotransmitter binds to the receptor,
a gate opens to allow ions to flow through a channel in the membrane into the interior of the post synaptic neuron.