PSYC 330 Lecture Notes - Lecture 4: Axon Hillock, Microglia, Myelin
27 Jan 2017
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Document Summary
Axon hillock is the last segment where information can be integrated. Myelin sheath serves as insulation, made up of fatty substance, also increases speed. Presynaptic (before synapse) axon terminals -> postsynaptic (after synapse) dendrites. There are many synapses onto 1 dendrite, there are many signals being given to one cell at any time. The discovery of nt"s: otto loewi"s nobel-prize winning experiment (1920) Chemicals in uid contained messengers that caused changes in muscle constractions in disconnected heart. Loewi called this chemical vagusstof -> later called acetylcholine. Basally (resting membrane potential) -> negatively charged (hyperpolarized( Generation of an actional potential: 1/1000 of a second. 1: threshold value (a bunch of sodium channels are opened, rapid depolarization (when all of these sodium channels are opened the cell becomes really. Once it hits the threshold there"s no going back. Increased speed of neuronal communication is part of maturation. Neurons must integrate (sum up) this information to reach action potential threshold.
