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A&P.nervous.action
| Question | Answer |
|---|---|
| resting membrane potential | plasma membrane creates slight difference between charge inside & outside the cell |
| what is potential difference in skeletal muscle cells? | -70 to -90 mV |
| what is the purpose of the sodium potassium pump? | moves NA+ and K+ through the plasma membrane AGAINST their concentration gradients |
| why is cell negative? | because it produces negatively charged proteins |
| the resting membrane potential is an equilibrium | established when K+ diffuses out of the cell - then becomes equal to the tendency of K+ to move back into the cell, because it is attracted to negatively charge proteins inside the cell |
| depolarizing | closer to zero - sodium is entering into the cell |
| repolarization | drops it to -70 - potassium is leaving the cell |
| sodium-potassium pump | flips |
| full action potential | as we depoarize, sodim enters cell |
| threshold | must cross threshold, sodium chaneels open, floods in, creates charge - makes cell more positive, sodium is in cell - crested - |
| repolarization | potassium starts to leave |
| refractory period | balances out - absolute & relative |
| refractory period | |
| Potassium & sodium are actively pumped out of the cell & then leak back inPotassium passes easily; sodium and chloride have a more difficult timeProteins are negative-cannot pass membrane IMBALANCE in voltage is a “potential” difference – ther |