Control of Cell Volume and
Membrane Potential
Slide 2
Basic problem
Basic solution
The cell at steady state
Typical ionic concentrations
Active pumping
Na+-K+
ATPase
Na+-K+
ATPase
Osmosis
The Nernst equation
Only very little ion
transfer
Electrical circuit model of
cell membrane
How to model Iionic
Two common current models
Electrodiffusion: deriving
current models
The short-channel limit
The long-channel limit
Volume control: The
Pump-Leak Model
Charge and osmotic balance
Steady-state solution
RVD and RVI
RVD and RVI
Lots of interesting unsolved
problems
Ion transport
Steady state equations
Transport control
IMCD cells
Active modulation of the
membrane potential: electrically excitable cells
Hodgkin, Huxley, and
the Giant Squid Axon
The
reality
Resting potential
Simplifications
Steady-state vs
instantaneous I-V curves
Example: Na+ and
K+ channels
K+ channel gating
Na+ channel
gating
Experimental data: K+
conductance
Experimental data: Na+
conductance
Hodgkin-Huxley equations
An action potential
The fast phase plane: I
The fast phase plane: II
The fast-slow phase plane
Oscillations
Where does it go from here?