Heart circulation and conducting system

What is Phase 1?

Atrial systole: the atria contracts, push blood to the ventricle

What is Phase 2?

Ventricular systole: the ventricle contracts, the atrioventricular valve closes, making the “LUB” sound

What is Phase 3?

Atrial and ventricular diastole: the semilunar valves close, making the “DUB” sound, atrium and ventricle is relaxed, filled with blood

What is the conducting system of heart?

sending electrical signal down to tell the heart when to contract

What are the system in order?

sinusatrial node, atrioventricular node, atrioventricular bundle (bundle of his) right and left bundles, subendocardial branches (Purkinje fibers)

SA node?

starts the electrical signal,atria contract

AV node?

briefly delays the signal so the ventricles have time to fill

Bundle of His?

carries the signal from the AV node into the ventricles

Bundle branches?

carry the signal down the interventricular septum

Purkinje fibers?

spread the signal through the ventricles, the ventricle contracts