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Name: sarah josephine uribe
Status: Student
Age: 12
Location: N/A
Country: N/A
Date: March 2004


Question:
What group of cells that adjusts the speed of heart beat?



Replies:
The pace maker cells do it but any cardiac muscle cell can do it if the pacemaker cells fail to do their job.

PF


There is a patch of cells in the upper right atrium called the sinoatrial node. They "fire" an action potential (bit of electricity) at a slightly faster rate than the rest of the cells around them. This is why it is sometimes called the "pacemaker" of the heart, because it sets the pace of the heartbeat. This wave of electricity then spreads from one cell to another throughout the atria (left and right) then passes to another bunch of cells called the AV or atrioventricular node. The atria then contract. Once the blood passes from the atria to the ventricles the wave of electricity passes to the venticular cells and they contract forcing the blood out of the heart.

vanhoeck



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