The heart doesn't pump electricity in the sense of pushing electrons through a circuit. Instead, it uses electrical signals to coordinate muscle contractions, creating the pumping action.
The Heart's Electrical System Explained
Here's a breakdown of how the heart generates and uses electrical impulses:
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The Sinoatrial (SA) Node: The Natural Pacemaker: Located in the right atrium, the SA node is a group of specialized cells that spontaneously generate electrical impulses. These impulses initiate each heartbeat.
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Electrical Pathway: The electrical signal from the SA node spreads throughout the heart along specific pathways.
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Atrial Contraction: The impulse first spreads across the atria (the upper chambers of the heart), causing them to contract and push blood into the ventricles (the lower chambers).
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Atrioventricular (AV) Node: The Relay Station: The electrical signal then reaches the AV node, which briefly delays the impulse. This delay allows the atria to finish contracting before the ventricles begin.
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Bundle of His and Purkinje Fibers: From the AV node, the impulse travels down the Bundle of His, then branches into Purkinje fibers. These fibers rapidly distribute the signal throughout the ventricles.
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Ventricular Contraction: The electrical stimulation causes the ventricles to contract, pumping blood to the lungs and the rest of the body.
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Repolarization: After contraction, the heart muscle cells repolarize, returning to their resting electrical state and preparing for the next impulse.
Analogy
Think of it like a series of dominoes. The SA node is the first domino. When it falls (generates an electrical impulse), it triggers the next domino (the atria to contract). This continues down the line until all the dominoes (the ventricles) have fallen (contracted).
In summary:
The heart doesn't pump electricity; it uses electrical signals, generated and conducted by specialized cells, to trigger and coordinate the mechanical contractions that pump blood throughout the body.
