Transcript The Neural Membrane at Rest

Membrane at Rest
Selectively Permeable Channels
Ion Concentration Differences
Nernst Relationship
Ion Pumps
Reflex Loop: Sensory-to-Motor
Water
Phospholipid Bilayer
Membrane is Impermeable
Channels Allow Ions to Pass
Protein Structure
Ion Channel
Potassium Channel
Potassium Channel Pore
Channels
Ion Concentrations and Nernst Potentials
Nernst Relation
E = 61.54 mV log10 [ion] out/ [ion]in
Lets call it 60 mV
Ion Concentrations and Nernst Potentials
Ion Transporters
Goldman Equation
Vm = 60 log10 Pk[Ko] + PNa[Nao]
Pk[Kin] + PNa[Nain]
Astrocytes Buffer Potassium
Questions
• What two functions do proteins in the neural
membrane perform to establish and maintain the
resting membrane potential?
• ON which side of the membrane are sodium ions
more abundant?
• When the membrane is at the potassium equilibrium
potential, in which direction (in or out) is there a net
movement of potassium ions?
• There is much greater concentration of potassium
ions inside than outside the membrane. Why, then is
the resting potential negative?
• When the brain is deprived of oxygen, the
mitochondria within neurons cease producing ATP.
What effect would this have on the membrane
potential? Why?
Next Class
• Chapter 4 The Action Potential