From 0808b4a65f30069e1530ca4b9db7b046e5aa3ea2 Mon Sep 17 00:00:00 2001 From: ackman678 Date: Thu, 29 Sep 2016 15:24:11 -0700 Subject: [PATCH] lecture03 post --- 2016-09-28-lecture03.md | 53 +++++++++++++++++++++++------------------ 1 file changed, 30 insertions(+), 23 deletions(-) diff --git a/2016-09-28-lecture03.md b/2016-09-28-lecture03.md index 157c703..1ee0ceb 100644 --- a/2016-09-28-lecture03.md +++ b/2016-09-28-lecture03.md @@ -24,18 +24,18 @@ as well as general molecular signaling within neurons as any living cell might h --- -## Neurons have a negative membrane potential at rest. +## Neurons have a negative membrane potential at rest -
+
* For intracellular recordings, an electrode is placed inside a cell such that the inside of the pipette is contiguous with the inside of the cell. If this electrode is connected to a voltmeter, which records transmembrane voltage across the cell membrane, one can determine the difference in voltage between the inside and outside of the cell. * When one does this in neurons, the microelectrode reports a negative potential called the resting potential. Always a fraction of a volt (-40 to -90 mV). -* Volts are a unit of electrochemical potential energy. 1 Volt will drive 1 coulomb of charge (6.24X1018 electrons) through a resistance of 1 ohm in 1 second. +* Volts are a unit of electrochemical potential energy. 1 Volt will drive 1 coulomb of charge (6.24x1018 electrons) through a resistance of 1 ohm in 1 second.
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Note: @@ -58,7 +58,7 @@ Pipe diameter ~ Resistance (ohms) = `R` Flow rate ~ Current (amperes) = `I` -`V = IR` Ohm’s law +`V = IR` **Ohm’s law** `I = V/R` @@ -130,14 +130,20 @@ This figure shows these 3 types of neuronal signals. --- -## Resting Potentials of Neurons +## Resting membrane potential of neurons + +
+
* The membrane of a nerve cell maintains an electrical polarization -* The cell is polarized: at rest, an electrical gradient is maintained across the plasma membrane (negative charge is greater inside the cell) -* The cell has a resting potential: difference in voltage across the membrane of a cell (~ -70 mV) -* The cell has a concentration gradient: difference in distribution of ions between the inside and outside of a membrane +* The cell is polarized– at rest, an electrical gradient is maintained across the plasma membrane (negative charge is greater inside the cell) +* The cell has a resting potential– difference in voltage across the membrane of a cell (~ -70 mV) +* The cell has a concentration gradient– difference in distribution of ions between the inside and outside of a membrane + +
+ +
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Note: @@ -252,7 +258,7 @@ There are also ion channels that form pores in the cell membrane that are select * Requires ATP * Helps set up the ion concentration gradients and resting membrane potential -
Alberts *Mol Biol of the Cell* Fig. 11-10
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Alberts *Mol Biol of the Cell* 3e Fig. 11-10
Note: @@ -268,7 +274,8 @@ Here is one these ion transporters— the Na-K pump that moves 3 Na out of the c * Show ion selectivity * Can be gated by different mechanisms -
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+ Note: @@ -446,17 +453,6 @@ T = 20+273 ==>58.26427 ---- - -## Electrochemical equilibrium video - -
Neuroscience 5e Animation 2.2
- - -Note: - - - --- ## Examples @@ -512,6 +508,17 @@ I = g(Vm-Ex). g = conductance, no. of open channels. (Vm-Ex) = driving force ca --- +## Electrochemical equilibrium video summary + +
Neuroscience 5e Animation 2.2
+ + +Note: + + +--- + + ## Membrane potential influences ion fluxes
Neuroscience 5e Fig. 2.6