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Basics: Difference between revisions
→Het ECG is een optelsom van de actiepotentiaaltjes van miljoenen cardiomyocyten.
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Because of the spreading of the impulse through the heart, the electric field changes continually in size and direction. The ECG is a graphical visualisation of the electric signals in the heart. | Because of the spreading of the impulse through the heart, the electric field changes continually in size and direction. The ECG is a graphical visualisation of the electric signals in the heart. | ||
= | =The ECG is a sum of the action potentials from milions of cardiomyocytes= | ||
[[Image:Hart_cells.png|thumb| | [[Image:Hart_cells.png|thumb|The heart consists of approximately 300 trillion cells]] | ||
[[Image:cells_in_rest.png|thumb|In | [[Image:cells_in_rest.png|thumb|In rest the heart cells are negatively charged. Trough the depolarization by surrounding cells they become positively charged and they contract.]] | ||
[[Image:Ion_currents.jpg|thumb| | [[Image:Ion_currents.jpg|thumb|During the depolarization sodium-ions stream inwards the cell. Subsequently the calcium-ions stream inwards the cell. These calcium-ions give the actual muscular contraction. Finally the potassium-ions stream out of the cell. During the repolarisation the ion concentration is corrected. On the ECG an action potential wave coming towards you is shown as a positive result. The ECG electrode is represented here as an eye.]] | ||
The individual [[action potential|action potentials]] of the individual cardiomyocytes are in fact averaged. The final result is actually the average of trillions of microscopic electronical signals | |||
{{clr}} | {{clr}} | ||