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The Synapse

The Synapse

Author: Meg O'Mahony

In order to demonstrate an understanding of the Synapse and how it conducts the nervous impulse to the next neuron, you need to be able to: 

  1. explain, with the use of labelled diagrams and a written explanation, the conduction of the nerve impulse            
    • at the synapse, including the role/structures of:

      • pre- and postsynaptic cells,

      • synaptic cleft,

      • neurotransmitters,

        • acetylcholine, dopamine, serotonin         


This tutorial explains what happens when the Action Potential reaches the end of an axon.  It begins with the voltage-gated Calcium channels and how the influx of Ca2+ allow for the vesicles filled with neurotransmitters to fuse with the end of the synaptic knob of the pre-synaptic neuron. The small (µm) diameter of the synapse makes diffusion an effective means of transport of the neurotransmitters to the receptors on the post-synaptic neuron, even though it costs some ms.  A combination of conformational change of the receptor proteins once the neurotransmitters bind and the chemical-gated channels around them generate the next Action Potential. Explanation of how the synapse is cleared of residual neurotransmitters as well as a short discussion of the different types of neurotransmitters completes this tutorial.

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The tutorial explores what happens to the Action Potential when it reaches the end of the axon. The synapse is the small space between the axon of one neuron and the dendrites of the next. Chemicals called neurotransmitters are used to transfer the potential across this gap.

Source: M. O'Mahony, open source images

Student Notes Template

Template for students to take notes from tutorial video. Includes the various figures.


Source: M. O'Mahony, open source figures

Synapse Animation

When you open this site, click on the figure of the synapse.  You will then see a powerpoint summary of what is happening in the synapse followed by some questions.  This is a very good overview of the events that happen at the synapse.  You can also download this ppt (look to the right) if you register.  It is worth downloading.

(I have not posted the presentation because of the copyright regulations covering items on TES.)

Source: Gemma Button on TES connect

HHMI: Animation on how toxins block synaptic function

This animation  from HHMI shows how the toxins from cone snails cause paralysis by blocking various functionalities of the synapse.  A follow up animation to this is also good:

Source: HHMI animations (links above)