%20Nervous%20System%20update

%20Nervous%20System%20update - *PLEASE REMEMBER TO DO THE...

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Unformatted text preview: *PLEASE REMEMBER TO DO THE MERCURY EVALUATIONS * From March 17- April 12. I t only takes 5 ­ 10 m inut es for students t o fill out e ac h of thei r course evaluat i ons and is a gre a t way fo r thei r voices to be heard and to i mpact pos i tive change in th e pro gram. The numerical results of these evalua t ions w i ll b e made availa b le to othe r McGill students who a re contem p lating taking the course . Students can access their course evalua t ions b y log g ing in t o their MI NERVA account where a p op ­ u p window will a ppea r pro mp ting stu d ents t o fi l l out t h eir evaluations. I f n o p op ­ u p window ap p ears, they ca n access the cou r se evaluations by: >Selecting Studen t Menu > Clicking on Mercu r y On l ine Course Evaluation Me n u > The n on Submit your course evaluations The Nervous The Nervous System Neurons in the Hippocampus Different Types of Neurons A Simple Reflex Arc Simple Resting Potential Given that the resting potential is necessary for nerve cell signaling: Where does it come from and how is it maintained? how Origins of the Resting Potential I Origins 15mM NaCl 150mM KCl 150mM NaCl 15mM KCl Cytosol Extracellular Origins of the Resting Potential II 15mM NaCl 150mM KCl 150mM NaCl 15mM KCl Cytosol Extracellular Origins of the Resting Potential III Origins Ionic Origins of the Resting Potential The Nernst Equation Equation An equilibrium potential is determined by the concentration gradient of the ion and the electrical charges carried by the ions. Ions will flow from high concentration to low due to a favorable free energy change. This change= -RT ln Co/Ci Ions will flow away from like charges and toward the opposite charge due to a favorable free energy change. This change= zFV. When the two flows are equal, i.e., at equilibrium, the two free energy values will also be equal. Thus: zFV-RT ln Co/Ci= 0, and the potential at which this occurs, the equilibrium potential, is: V=(RT/zF)ln Co/Ci Converting to log10 and substituting values for constants we get: Veqb=58(log10 Co/Ci) at 20oC and Veqb=61.5(log10 Co/Ci) at 37oC Equilibrium Potentials for Ions in Squid and Mammalian cells and For the squid (at 20oC): Na+ = +55mV K+ = -81mV Cl- = -66mV For a mammal (at 37oC): Na+ = +68mV K+ = -97mV Cl- = -93mV A Bacterial Potassium Channel Ion Selectivity in a Potassium Channel Ion Ion Permeation of a Potassium Channel Ion he Conduction of N er ve I mpulses How do we get information from one end of the nervous system to the other? Passive (Decremental) Conduction by Axons Passive How do we get to the Big Toe?? Responses of Nerve Cells to Electrical Stimulation Responses The First Recorded Action Potential The Ionic Basis of the Action Potential The Ionic currents Ionic currents During the Action potential Conduction of Action Potentials Conduction Down an Axon Molecular Structure of Voltage Gated Channels Voltage Gated Sodium Channel Mechanisms During the Action Potential Action Channel Inactivation Channel Synaptic T r ansmission Neurons and Synapses In the Brain Neuromuscular Junction EM Images of Synapses EM Generic Synapse Generic The Neuromuscular Junction The Neuromuscular Junction Function Neuromuscular Nerve Conduction and Muscle Contraction Nerve The Neuromuscular Transmitter The Synaptic Release and Recycling Synaptic The Nicotinic Receptor The Muscarinic Receptor The Other Transmitters Other ...
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