Synapse

- Nerve impulses are transmitted through a functional gap or intercellular space Synapse

between neurons called the synapse or the synaptic gap. Although nerve impulses are

conducted electrically within the neuron, in the synapse they are continued through a

special group of chemicals called neurotransmitters.

See also Synapse on Gale

- Stimulus 1 produces a depolarization (EPSP) and stimulus 2 produces Spatial Summation

a hyperpolarization (IPSP). The summated change in membrane potential at the axon

hillock does not exceed threshold, therefore an action potential does not occur.

- results when two action potentials arrive in very close succession Temporal Summation

at a single presynaptic terminal. The first action potential causes a local depolarization in

the postsynaptic membrane that remains for a few milliseconds before it disappears,

although its magnitude decreases through time. Before the local depolarization caused by

the first action potential repolarizes to its resting value, a second action potential

initiates a second local depolarization. Temporal summation results when the second local

depolarization summates with the remainder of the first local depolarization. If the

summated local depolarization reaches threshold at the axon hillock, an action potential is

produced in the postsynaptic neuron.

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- Neurotransmitters are chemical agents secreted at the end of axons Neurotransmitter

of nerve cells that diffuse across the synaptic gap and transmit information to adjoining

cells such as neurons, muscle cells, and glands by altering their electrical state or activity.

There are many neurotransmitters with a variety of structures and functions; two of the

principle ones are acetylcholine and norepinephrine.

See also Neurotransmitters or Neuroplasticity

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Citations

1. Fitzke, Frederick W., et al. "Spatial summation for single line and multi-line motion stimuli."

Perimetry Update 2002/2003. Kugler Publications, 2002. 335+. Academic OneFile. Web. 11 Oct.

2012.

2. "Neurotransmitter." The Gale Encyclopedia of Science. Ed. K. Lee Lerner and Brenda Wilmoth

Lerner. 4th ed. Detroit: Gale, 2008. Student Resources in Context. Web. 11 Oct. 2012.

3. "Synapse." The Gale Encyclopedia of Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. 4th ed.

Detroit: Gale, 2008. Student Resources in Context. Web. 15 Oct. 2012.

4. Curatolo, . Assessment of regional analgesia in clinical practice and research; Electrophysiological

methods. 2000. Photograph. British Medical BulletinWeb. 11 Oct 2012.

<http://bmb.oxfordjournals.org/content/71/1/61.full>.

5.The Whacky, Wild and Misleading World Of Neurotransmitter Testing. 2009. Photograph. Primal Body

Primal MindWeb. 11 Oct 2012. <http://www.primalbody-primalmind.com/?p=366>.