1. Neurophysiology

1. Neurophysiology - Neurophysiology I Anatomy...

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Neurophysiology I. Anatomy- Structure/function a. Neuron nerve cell i. Dendrite- main input ii. Soma-cell body iii. Hillock-action potential starts iv. Axon- main output v. Terminals II. Basis of electrical activity a. Equilibrium potential (Epot) i. Theoretical, not actual when looking at cell ii. Mu ion=RTln[(ion]in/[ion]out) iii. Chemical activity with concentration gradient iv. Electrical activity with +/- charge pull v. At equilibrium- no flow one way or other vi. Nerst equation 1. Eion=RT/ZF ln ([ion]out/[ion]in) 2. Derivation to Eion=61/z log([ion]out/[ion]in) b. Membrane potential (Vm) i. Measuring difference of voltage in/out ii. Force ion= Vm- Eion 1. If Vm is far from Eion then large force moves ion 2. If Vm=Eion then no force/ no net movement iii. Conductance 1. The ability for an ion to cross a membrane (Gion) 2. Similar to permeability iv. Ionic current (Iion) 1. Number of ions crossing/charge crossing 2. Iion= Gion (Vm- Eion) 3. Or Iion=Gion*Fion 4. Iion requires driving force (Fion) 5. And a pathway (Gion) 6. Without either then there is no ion/current movement 7. When moving a cation I/Fion is positive when cation is leaving cell and negative when cation is going into cell 8. When moving an anion I/Fion is negative when anion is leaving the cell and positive when anion is entering the cell v. VI plots 1. X-axis is Vm and y-axis is I 2. Y=m(x-b); Iion=G(Vm.-Eion) 3. Reversal potential when current (+/-) a. Equilibrium potential w/single ion b. Slope of VI plot is conductance c. Ions cross easily with steep slope- visa versa c. Resting potential (Vrest) i. membrane potential w/o firing action potential
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ii. leak channels are open at rest
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1. Neurophysiology - Neurophysiology I Anatomy...

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