This section is important to understand because the Signalife Monitoring System detects electrical currents in the heart and should be able to detect and monitor other body parts with future applications. One should know some basics about electricity and how the human body’s phenomenon of creating electricitytakes place. Atoms of all kinds can lose or gain electrons and this changes the electrical property slightly of that atom. When you walk across a rug your body can pick up or rub off extra electrons from the rug. These electrons are now on your body and slightly change your body’s electrical potential and will need to go somewhere, so when you touch the door knob the slight electrical shock you get is the electrons leaving your body. The cells of the heart in a resting state are actually electrically polarized — that means the inside of the cell has negative electrical charge due to certain atoms of potassium, sodium, chloride and calcium which naturally have gained a few extra electrons and are therefore a bit negatively charged. The outside environment of these cells is positive — therefore you have what is called polarity (two poles having opposite properties — one negative and one positive). This difference creates an electron fl ow (like the rug example) and that is basically what electricity or electrical fl ow is all about. The cells have a membrane and the membrane has what is referred to as membrane pumps, which are actually microscopic passageways that open and close and allow some of the negative atoms in the cell to leave — changing the cell internally from negative to positive, since less negative atoms are now inside the cell.This loss of negativity is called depolarization and depolarization is the basic electrical event of the heart cells and the heart itself. As one cell depolarizes it creates a chain reaction to the cell next to it and the electrical current is on its way from one cell to another — through millions of cells in an instant. This cell to cell wave of depolarization is a fl ow of electricity, an actual electrical current and can be detected by ECG equipment. This takes less than a second to fl ow through the entire heart. Then the cells go back to normal (where the inside of the cell goes back to being negatively charged) and this process is called repolarization. Repolarization can also be detected by ECG equipment. When the cells go back to normal, it is because the membrane opens up and allows some negative atoms back in the cell. This activity of the membrane pumps (the workhorse of the cell membrane) opening and closing constantly is an amazing act of nature. Every diff erent signal and wave form shown on an ECG is a manifestation of these two processes: depolarization and repolarization.
Xanya Sofra Weiss
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