Lecture notes. Taken in part from: Adley, D. J. (1991) The Physiology of Excitable Cells , Cambridge,3ed. Calabrese, R. C., Gordon, J., Hawkins, R., & Qian, Ning. (1995) Essentials of neural Science and Behavior. Study guide and practice problems . Appleton & Lange
PHYSICAL PROCESS THAT EQUILIBRATES FREELY MOVING SUBSTANCES
0.1 M NaCl = 0.1 M Na + 0.1M Cl = 0.2 Osm
1) The potential difference that builds up in the above system is expressed as voltage (in mVolts).
Voltage should be thought of as a gradient. A gradient implies looking at two places or states with respect to one another.
If Compartment 1 is the reference chamber, Compartment 2 is said to be positive with respect to compartment 1. (A volt meter will point toward the positive pole).
2) This can be thought of as an electromotive force.
3) Think of this voltage as a driving force for the movement of charges in space.
δW =increment of work
δn = increment of number of moles moved.
R =gas constant (8.314 J deg-1 mole-1)
T =absolute temperature
X =molar concentrations of solute in
compartment 1 an 2
δWe = δn (zFE)
δWe = increment of work.
δn = moles moved against an electrical
Z = valence of the ion moved.
F = Faraday’s constant(96,500).
E = the potential difference between the