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Unformatted text preview: Many drugs (and toxins) act on ion channels, often mimicking the action of endogenous neurochemicals. Ions are either pumped or flow passively through ion channels. Ion channels can be represented by a battery and a conductance in series. They mostly have molecular weights in the range of 25K to 250K Daltons. Question 5 Assume you are studying a glial cell whose membrane potential of -90mV is due to a K+ gradient across the membrane. Suppose you dump a potassium salt in the extracellular fluid, which doubles the potassium concentration outside the cell. Which of the following do you expect to happen: Answer The membrane potential will move in the positive direction. The membrane potential will move in the negative direction. The membrane potential will not change. The membrane potential will move gradually to a more positive value as the pumps slowly return the the membrane potential to its equilibrium state....
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This note was uploaded on 02/09/2012 for the course BME 402 taught by Professor Mel during the Spring '06 term at USC.
- Spring '06