Neuroscience Test outline II

Neuroscience Test - Ch 4 Neural Conduction and Synaptic Transmission I The Lizard(A case of Parkinson's Disease A Roberto Garcia d'Orta B Has

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Ch. 4: Neural Conduction and Synaptic Transmission I. The Lizard (A case of Parkinson’s Disease) A. Roberto Garcia d’Orta B. Has Parkinson’s Disease (1 st sign was a tremor) C. Went from a vigorous man into a lizard (rigid muscles, spontaneous movements, difficulty in starting to move, slowness in executing voluntary movements) D. “Reptilian Stare”- a term used to describe the characteristic lack of blinking and the widely opened eyes gazing out of a motionless face E. What happened? 1. Nerve cells called substantia nigra (black substance) unaccountably dying. 2. These cells make dopamine, which is delivered to “striatum”(part of the brain that helps to control movement) 3. As cells die, dopamine levels go down 4. Without dopamine the striatum cannot function properly II. The Neuron’s Resting Membrane Potential A. Membrane Potential - the difference in electrical charge between the inside and the outside of a cell. B. Microelectrodes -electrode that is placed within the cell (intracellular); must be fine enough to pierce the neural membrane without severely damaging it C. Resting Potential -steady membrane potential of about -70millivolts (at this state, the neuron is said to be polarized ) D. Resting potential results from the fact that the ration of negative to positive charges is greater inside the neuron than outside. E. Four kinds of ions contribute significantly to the resting potential 1. Sodium ions (Na+) ; concentration is greater outside in resting state 2. Potassium ions (K+) ; more concentration inside in resting state 3. Chloride ions (Cl-) ; concentration is greater outside in resting state 4. Various negatively charged protein ions (made inside the neuron and for the most part stay put) F. Factors 1. Equal distribution factors Random motion -ions in neural tissue are constantly moving around and they tend to become evenly distributed because they are more likely to move form areas of high concentration to areas of low concentration than vice versa (more likely to move down their concentration gradient ). Electrostatic Pressure -any accumulation of charges, positive or negative, in one area tends to be dispersed by the repulsion among the like charges in the vicinity and the attraction of opposite charges concentrated elsewhere.
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G. Passive -it does not involve the consumption of energy H. Active -does involve consumption of energy I. Efflux -outflow J. Influx -inflow K. Sodium - potassium pumps -Active transport mechanisms that pump Na+ ions out of neurons and K+ ions in III. Generation and Conduction of Postsynaptic Potentials A. Depolarize -decrease the resting membrane potential (from -70 to -67mV) 1. Postsynaptic depolarizations are excitatory postsynaptic potentials (EPSP) because they increase the likelihood that the neuron will fire B. Hyperpolarize -increase the resting membrane potential (-70 to -72 mV) 1. Postsynaptic hyperpolizations are called inhibitory postsynaptic potentials (IPSP) because they decrease the likelihood that the neuron will
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This note was uploaded on 04/29/2008 for the course NSC 1306 taught by Professor Patton,keale,diaz-granados,weaver during the Spring '07 term at Baylor.

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Neuroscience Test - Ch 4 Neural Conduction and Synaptic Transmission I The Lizard(A case of Parkinson's Disease A Roberto Garcia d'Orta B Has

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