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PSY 241 Lecture 2
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Neuronal Membrane
Made up on phospholipid bilayer
Prevents most substances from freely passing
5 Ions that Surround Membrane
Cations(positively charged):
Sodium (NA+)
Potassium (K+)
Calcium (Ca
2+
)
Anions (negatively charged):
Chloride (Cl-)
Negatively charged proteins (A-)
Distribution of ions across the neuronal membrane
Outside:
Sodium
Chloride
Calcium
Inside:
Potassium
Negatively charged proteins
Ion Movement
K+ and Cl- __________
Na+ and Ca2+ do ____________
A- proteins ARE ___________
K+ and Cl-
PASS FREELY
Na+ and Ca
2+
do
NOT PASS EASILY
A- proteins
ARE IMPERMEABLE
Diffusion
Spontaneous spread of molecules until a uniform concentration is achieved
Electrostatic pressure
Propensity of charged molecules or ions to move, via diffusion, toward areas with the opposite charge
Intracelluar microelectrode
:
A conductive medium that can be used to ___________________ or _________ electrical potentials.
A conductive medium that can be used to
apply electrical current
or
record
electrical potentials.
Resting membrane potential (-60 mV)
Neuron is more negative inside relative to outside of cell
Sodium-potassium pump
excludes 3 Na
+
ions for every 2 K
+
ions taken into the cell
Requires energy supplied by ATP, which is converted to ADP
What happens if you allow Sodium to pass easily?
Sodium rushes into the cell
Not at resting potential
Insert channels and Sodium
Equilibrium potential
Potential at which force of diffusion is balanced by the force of electrostatic pressure
no net movement of the ion
K+ has equilibrium potential of -90 mV
Na+ has equilibrium potential of +55 mV
The resting membrane potential can be simply altered by
simply changing the permeability of the membrane
Author
ralejo
ID
200614
Card Set
PSY 241 Lecture 2
Description
PSY 241 psychobiology
Updated
2/14/2013, 10:24:57 PM
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