PHGY 209 Lecture Notes - Lecture 3: Cell Membrane, Postsynaptic Density, Grey Matter
16 Sep 2016
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Document Summary
Action potentials don"t propagate normally: myelin is very fatty and as a result is white in colour, white matter and gray matter in the brain. Gray matter: cell bodies, dendrites, synapses: white matter: large bundles of axons. There are three main types of synapses: axodendritic synapse. Shaft synapse o axosomatic synapse o axoaxonic synapse a single neuron, through its branching axon may make synapses with many other neurons. The neuron can send out one signal (action potential) but a copy of it can go to multiple regions in the nervous system. The ends of axons have a swelled region called a presynaptic terminal: narrow gap between presynaptic terminal and postsynaptic spine called the synaptic cleft. Spherical plasma membrane vesicles within presynaptic terminals they hold the neurotransmitter chemicals o some vesicles are randomly distributed reserve pool (back-up: vesicles involved in releasing transmitter is docked in the region that faces synaptic cleft.
