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Flashcards in Biophysics Deck (6)
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What is the membrane potential

The difference between the electrical potential in the cytoplasm and the electrical potential in the extracellular space.


How is the membrane potential measured

An intracellular electrode is used to measure the transmembrane potential with respect to the electrical potential of the extracellular solution


What is the extracellular concentration of K, Na, Ca, Cl and HCO3 respectively

4.5, 145, 1.0, 116,24


What is the intracellular concentration of K, Na, Ca, Cl and HCO3 respectively

120, 15, 0.0001, 20, 15


Is the Na K pump electronegic and what does this mean

Yes, displacement of charge generates an electrical current


What 3 channel types are associated with maintaining the resting Vm

Na/KATPase - Loss of positive charge, contributes 20% of -70mV
K channels - 80% of resting Vm - Movement of K out removes positive charge from inside the cell creating a potential difference across the membrane
Na channels - Cell at rest has low permeability to Na - however influx of Na into the cell leads to repulsion of other Na ions - K channels are leaky and let a few Na ions through