Archive for August 8th, 2019

August 8, 2019

Autorhythmicity

automaticity

Autorhythmicity [aw-toh-rith-miss-uh-tee], or automaticity, refers to the heart’s ability to spontaneously generate an electric charge without outside help. Cardiac electrical activity originates in the sinoatrial node (SAN) and is propagated via the ‘His-Purkinje’ network, the fastest conduction pathway within the heart. This pathway is known as the electrical conduction system of the heart.

The electrical signal travels from the SAN, which stimulates the atria to contract, to the atrioventricular node (AVN), which slows down conduction of the action potential from the atria to the ventricles. This delay allows the ventricles to fully fill with blood before contraction. The signal then passes down through a bundle of fibers called the ‘bundle of His,’ located between the ventricles, and then to the ‘purkinje’ fibers at the bottom (apex) of the heart, causing ventricular contraction.

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