Synapse

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The synapse is a specific site where neuronal signals are transmitted from cell to cell. It is a structure where the electrical signals of one neuron are converted to chemical signals in order to transmit information from one nerve cell to the next nerve cell(s). Postsynaptic cells are separated from presynaptic cells by a synaptic cleft. The electrical potential in the presynaptic cell changes which causes the cell to release a neurotransmitter signalling molecule by exocytosis. The neurotransmitter moves across the synaptic cleft and triggers an electrical change in the postsynaptic cell[1].

A chemical synapse is the distinguishable gap (between 15-200nm wide)[2] between the axon terminal of one neuron cell and the dendrites of another. Electrical signals are able to continue across a chemical synapse due to the activity of neurotransmitters[3]. Neurotransmitters are chemicals such as acetylcholine or dopamine.

An electrical synapse is a physical connection between two neurones and electrical signals are able to pass straight through from one neurone to the other without the help of neurotrasmitters[4].

What happens at the Cholinergic Synapse?

Transmisson of an action potential across a synapse commonly involves Acetylcholine (Ach), a common neurocrine, neurones which secrete Ach are cholinergic[5].

References

  1. Bruce, A, Johnson, A, Lewis, J, Raff, M, Roberts, K and Walter, P (2008). Molecular Biology of the Cell. Fifth Edition. New York: Garland Science, Taylor and Francis Group, LLC. p682.
  2. http://michaeldmann.net/mann13.html
  3. http://www.mind.ilstu.edu/curriculum/neurons_intro/neurons_intro.php
  4. http://www.mind.ilstu.edu/curriculum/neurons_intro/neurons_intro.php
  5. Silverthorn. D.U., 2007. Human Physiology an Integrated Approach. 4th Edition. San Francisco: Pearson Education Inc.
  6. Silverthorn. D.U., 2007. Human Physiology an Integrated Approach. 4th Edition. San Francisco: Pearson Education Inc.
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