Each of the two upper chambers of the heart from which blood is passed to the ventricles.
Note: The right atrium receives deoxygenated blood from the veins of the body, the left atrium oxygenated blood from the
pulmonary vein.
Source:
PAC, 2016, 88, 713. 'Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)' on page 728 (https://doi.org/10.1515/pac-2015-1202)