What makes me nervous?

7. Synapse
Synapse- Nerve impulses are transmitted through a functional gap or intercellular space
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
Spatial Summation- Stimulus 1 produces a depolarization (EPSP) and stimulus 2 produces
a hyperpolarization (IPSP). The summated change in membrane potential at the axon
hillock does not exceed threshold, therefore an action potential does not occur.
Temporal Summation- results when two action potentials arrive in very close succession
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

8. summated local depolarization reaches threshold at the axon hillock, an action potential is
produced in the postsynaptic neuron.
5
Neurotransmitter- Neurotransmitters are chemical agents secreted at the end of axons
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
5
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.

9. 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>.