PSYC 211 Chapter Notes - Chapter 2.6: Excitatory Postsynaptic Potential, Exon, Resting Potential
3 Jun 2016
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Membrane elsewhere due to the presence of receptors and the protein filaments which hold them in place. When action potentials are conducted down an axon something happened inside all of the terminal buttons. This docking is accomplished when clusters of protein molecules attach to other protein molecules located in the presynaptic membrane. The release zone of the presynaptic membrane contains voltage-dependent calcium channels. When the membrane of the terminal buttons is depolarized, the calcium channels open: calcium ions are located in the highest concentration in the extracellular fluid and thus they flow into the cell when the channels open. The entry of calcium ions is an essential step: if neurons are places in a solution that contains no calcium ions, an action potential no longer causes the release of neurotransmitter. This event makes the segments of the clusters of protein molecules move apart, producing a fusion pore, a hole through both membrane that enables them to fuse together.
