Heart Action Potential

Question

Why do action potentials flow through the muscle cells instead of directly from atria to ventricles?

Answer 1

Hi Ashley, in a sense, you could say that the action potential of the heart does in fact flow from the atria to the ventricles via the cardiac myocytes (Heart muscle cells).

In a healthy individual the action potential will begin at the SA node and travel to the AV Node. The electrical signal traveling through these two nodes will allow both of the atria to contract. Following the contraction of the atria, the AV node will slightly delay the electrical signal before passing the signal down to the inter ventricular septum (via the Bundle of His) and the left and right bundle branches. Once the signal reaches the apex of the heart, the Purkinje fibers (surrounding both of the ventricles) will allow the ventricles to contract.

Please feel free to reach out if you need further explanation!