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handout21 - BIPN 100 Dr. Fortes TA Jing Wang Handout 2...

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Unformatted text preview: BIPN 100 Dr. Fortes TA Jing Wang Handout 2 jiw004@ucsd.edu OH Wed 4-5 @ Caf Roma 1. Myelin/Glial Cells A. Insulate axon MB to prevent leakage of ions no channels inserted where myelin is B. Allow faster conduction velocity of AP C. Reduces requirement to maintain conc. gradients under myelin (not at nodes), which saves a lot of ATP D. CNS: oligodendroglia myelinate several axons E. PNS: many Schwann cells myelinate a single axon by wrapping around it and leaving space between each other F. Glial cells non-excitatory neuronal cells used to support excitable neurons i. Epindymal cells: line cavities of the CNS, secrete cerebrospinal fluid (CSF) ii. Microglia: act like immune cells iii. Astrocytes: participate in uptake of K+ and certain NTs, form part of the blood-brain barrier (BBB) 2. Synaptic Transmission A. Electrical Synapses electrical signal (current) passes directly from one cell to the next via gap junctions i. Gap junctions connect the cytosol of two adjacent cells through a channel ii. Regulation of a system as a whole instead of individual neurons B. Chemical Synapses Synapse that uses NTs/hormones to communicate with target cell C. Pre-Synaptic events Release of NT (fig 8.20) i. NT can be excitatory or inhibitory to the target cell (a) AP reaches axon terminal depolarization opens V-G Ca++ ch. (b) Ca++ flowing in bind regulatory proteins (c) Synaptic vesicles release NT via exocytosis D. Post-Synaptic Events NT diffuses across synaptic cleft, binds its receptor (fif 8.22) i. Fast response - Receptor is a Ligand-Gated ion channel conformational change opens channel ii. Slow response - Receptor is a G-protein coupled receptor (GCPR) 2 nd messengers used to transmit signal E. Removal of NT-signal transmission i. Removal by Reuptake Nts get taken back up by the neurons/vesicles that released them...
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This note was uploaded on 04/14/2008 for the course BIPN 100 taught by Professor French during the Winter '07 term at UCSD.

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handout21 - BIPN 100 Dr. Fortes TA Jing Wang Handout 2...

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