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Actiepotentiaal: verschil tussen versies
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| Regel 4: | Regel 4: | ||
This action potential entails a number of phases; | This action potential entails a number of phases; | ||
*'' 'Phase 4''', also known as the resting phase. The membrane potential is at -90mV | *'''Phase 4''', also known as the resting phase. The membrane potential is at -90mV | ||
*'' 'Phase 0''' fast sodium channels open and sodium flows into the cell (depolarises). This results in the rapid upstroke. | *'''Phase 0''' fast sodium channels open and sodium flows into the cell (depolarises). This results in the rapid upstroke. | ||
*'' 'Phase 1''', potassium flows from the cell (efflux) which increases the membrane potential restores to 0mV | *'''Phase 1''', potassium flows from the cell (efflux) which increases the membrane potential restores to 0mV | ||
*'' 'Phase 2''', also known as the plateau phase. This phase is characterized by potassium efflux and calcium influx. | *'''Phase 2''', also known as the plateau phase. This phase is characterized by potassium efflux and calcium influx. | ||
*'' 'Phase 3''', the potassium efflux exceeds the calcium influx. The membrane potential decreases to 90mV (repolarization). | *'''Phase 3''', the potassium efflux exceeds the calcium influx. The membrane potential decreases to 90mV (repolarization). | ||
[[Image:actionpotential.png | thumb | The action potential of a cardiomyocyte has several phases and ion currents.]] | [[Image:actionpotential.png | thumb | The action potential of a cardiomyocyte has several phases and ion currents.]] | ||
As adjacent cardiomyocytes depolarize, a domino effect is set in motion: the depolarization wave. This depolarization wave is registered on the ECG. | As adjacent cardiomyocytes depolarize, a domino effect is set in motion: the depolarization wave. This depolarization wave is registered on the ECG. | ||