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Atrium (heart) facts for kids

Kids Encyclopedia Facts
See also: Atrium (architecture) and Atrium, Cardiff
Diagram of the human heart (cropped).svg
Front view of heart showing the atria
Latin Atrium

The atrium (Latin ātrium, “entry hall”) is the upper chamber through which blood enters the ventricles of the heart. There are two atria in the human heart – the left atrium receives blood from the pulmonary (lung) circulation, and the right atrium receives blood from the venae cavae (venous circulation). The atria receive blood while relaxed (diastole), then contract (systole) to move blood to the ventricles. All animals with a closed circulatory system have at least one atrium. Humans have two atria.

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Atrium (heart) Facts for Kids. Kiddle Encyclopedia.