measured in millivolts (mV)
| Ion | Extracellular Concentration |
Intracellular Concentration |
Relative Permeability |
|---|---|---|---|
| Na+ | 140 | 12 | 1 |
| K+ | 4 | 135 | 50 - 75 |
| Cl- | 150 | 5 | 10 |
| A- | 0 | 65 | 0 |
effect of sodium-potassium pump
3 Na+ out for 2 K+ in
effect of K+ movement alone
Nernst equation for K+ equilibrium potential 2
EK+ = –60 log10[Ci]/[Co] mV
–92 mV
effect Na+ movement alone
Nernst equation for Na+ equilibrium potential
ENa+ = –60 log10[Ci]/[Co] mV
+64 mV
effect Cl- movement alone
Nernst equation for Cl- equilibrium potential
ECl- = +60 log10[Ci]/[Co] mV
-89 mV
effect of Na+ and K+ concurrent movements
potassium flows out along chemical gradient
sodium flows in along electrochemical gradients
sodium-potassium pump
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[ Anatomy & Physiology 1 syllabus ] [ Page created 20 July 1999 ][ Last update 03 November 2005 ] [ Questions about this lecture? E-mail me ] |