Hearts Electrical System (the thump thump!)
Wonder what give your heart that kick to thump? That thump is actually from an electrical system that works within the heart! This electrical system is what keeps the heart pumping blood throughout the body to achieve perfusion.
SA-> Sinoatrial node (also known as the sinus node.)
AV-> Atrioventricular node
Normal impulses begin in the sinus node. The impulses travel across both atria causing them to contract which pushes the blood out of the atrium. From here the impulses cross a bridge of special electrical tissue between the atria and ventricles called the atrioventricular node. The signal here is slowed for about one to two tenths of a second to allow blood to pass from the valve to the ventricles. The impulses then exit the AV node and spread throughout both ventricles causing them to constrict, pushing blood into the arteries.
SPECIAL:
Cardiac muscle cells have a characteristic called automaticity which isn’t found in any other type of muscle cells. Automaticity allows a cardiac muscle cell to contract spontaneously without a stimulus from a nerve source. Meaning if no impulse arrives from the SA node to the rest of the cells, they will create their own impulses stimulating the contraction of the heart. They are not as affective and will be at a generally slower rate.
*This is due to the Anatomic Nervous System (Click Here to learn more about the anatomic nervous system).
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