Basics: Difference between revisions

Basics (view source)

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   An ECG is a registration of the heart's electric activity.
-Just like skeletal muscles, the heart is electrically stimulated to contract. This stimulation is also called ''activation'' or ''excitation''. Cardiac muscles are electrically charged in rest. The inner side of the cell is negatively charged '''''~t.o.v.~''''' the outside (resting potential). If the cardiac muscle cells will be electrically stimulated (depolarisation: the inner site of the cell will now be positively charged '''''~tov~''''' the outer site) and there comes an ~action potential~, the cells contract.
+Just like skeletal muscles, the heart is electrically stimulated to contract. This stimulation is also called ''activation'' or ''excitation''. Cardiac muscles are electrically charged in rest. The surface of the cell is positively charged relative to the inside (resting potential). If the cardiac muscle cells are electrically stimulated (depolarisation: the outside of the depolarized region is positively charged relative to the inside) and there comes an ~action potential~, the cells contract.
 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.