Cardiac Automaticity

Cardiac automaticity is the intrinsic ability of the heart to spontaneously depolarise, sending action potentials throughout heart muscles and myocardium. Unlike most organs in the human body, it does not require a nerve impulse to contract.

Surrounding the heart are nodal cells which send electrical signals throughout the heart. They comprise the following nerves in order: SA node, AV node, bundle of His, left and right bundle branches and the Purkinje fibres. The SA node (sinoatrial node) is the “pacemaker” and sets the rhythm for the heart. It sends action potential throughout the nodal cells, causing the myocytes to contract.

This ability of intrinsically contracting is what makes heart transplants possible. Thus, only oxygen is needed to be supplied so that it can “live” outside the body.

https://www.livescience.com/44460-heart-facts.html

https://youtu.be/1kX6Tp8CWFw

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