Anatomy of the Heart

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Systole Phase

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The cardiac cycle is the sequence of events that occur when the heart beats. There are two phases of this cycle:

• Diastole - Ventricles are relaxed.

• Systole - Ventricles contract.

Cardiac Cycle Systole Phase

Systole

Contraction passes from AV node to Purkinje fibers and ventricular cells. Ventricles contract. Atrioventricular valves close. Semilunar valves open. Blood is pumped from the ventricles to the arteries.

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Cardiac Cycle

Cardiac Conduction

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