One of the heart chambers.
hog:0000328 right atriumhog:0000369 left atriumhog:0000385 interatrial septumhog:0000602 atrium myocardiumhog:0000606 atrium endocardiumhog:0000941 atrium cardiac jellyhog:0001472 atrioventricular valveBFO:0000050 part of
hog:0000276
tao:0000471