L05-Synapses

L05-Synapses - Synapses Studying for the Test(50 multiple...

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2/1/07 Synapses Studying for the Test (50 multiple choice) o Anything in the book o History of Physiological Psychology o Ionic basis for the RMP o Ionic basis for the Action Potential o Propagation of the Action Potential o Synapses o Neurotransmitters o Neurotransmitter receptors o Postsynaptic potentials Facts of the Day o The transport rate for a single sodium pump is about 195 sodium ions and 130 potassium ions per second o There are about 1000 pumps per micron squared of membrane surface o There are about 1 million sodium pumps in a small neuron Ionic Basis of the Action Potential o After hyper polarization: point right after action potential where membrane potential is more hyperpolarized (more negative) than the resting membrane potential; caused by potassium ions flowing out of the cell o B-C is depolarization; C-D is repolarization; D-E is hyperpolarization Propagation of Action Potential in an unmyelinated axons o Flows smoothly along length of axon o Active process depending on passive properties of electrical potential o Spread of current down the axon as sodium channels open o Refractory period keeps current from flowing backward toward the soma Conduction in Myelinated Axons o Node of Ranvier: only place where voltage-gated sodium-potassium channels exist o Myelinated is much faster than unmyelinated Propagation of Action Potential o Action potentials occur with stimulation above the threshold voltage (All or None) o Action potential is carried by sequential opening of voltage-gated sodium channels and influx of sodium ions
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This note was uploaded on 04/09/2008 for the course PSYC 220 taught by Professor Brunges during the Spring '07 term at UVA.

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L05-Synapses - Synapses Studying for the Test(50 multiple...

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