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How do the atria and ventricles work together to move blood through the heart?
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Circulatory system
Human circulatory system.
The atria and ventricles function as a coordinated, two-stage pump to move blood through the circulatory system. This process, known as the cardiac cycle, relies on the alternating contraction (systole) and relaxation (diastole) of these chambers.1
- Atrial Function: The atria serve as reservoirs that receive blood returning to the heart. When the atria contract, they propel blood through the atrioventricular valves and into the ventricles.213
- Ventricular Function: The ventricles are the heart's primary pumping chambers, featuring thick, muscular walls designed to exert the force necessary to drive blood out of the heart. As the ventricles contract, the atrioventricular valves close to prevent backflow, and the pressure forces blood through the semilunar valves into the pulmonary artery or the aorta.431
This rhythmic coordination ensures that blood flows in only one direction, maintaining the pressure required to circulate oxygenated and deoxygenated blood throughout the body.31