When the heart beats, an electrical signal passes from the top of the heart, near the atria (upper chambers), down through the ventricles (lower chambers), and the chambers contract in that order.
Atrioventricular valves lie between the atria and ventricles, and semilunar valves are located at the bases of the two large vessels leaving the heart.
房室瓣放在心房和心室和半月瓣之间位于离开心脏的二艘大船的基地。
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During diastole, the atria and ventriclesof your heart relax and begin to fill with blood.