Biology / Unit 13 Bio 3201 short lesson, about 20 seconds
SA Node and the Cardiac Conduction System
Captions available
The idea
The sinoatrial node generates the heart's own electrical rhythm and initiates each cardiac cycle, its signal spreading through a pathway that coordinates chamber contraction timing.
In practice
A damaged sinoatrial node can be replaced functionally by an artificial pacemaker generating the same signal.
Where people slip
The rhythm originates at the sinoatrial node — nervous input adjusts rate but does not initiate each beat.
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