Term: atrium cardiac chamber ballooning
Name: atrium
Synonyms:
Definition: Cavitated compound organ that receives inflow of deoxygenated blood and delivers it to a muscular cardiac ventricle. Valves are present to direct flow. There are only two chambers present in the fish heart.
Ontology: Anatomy Ontology [ZFA:0000471]

Name: cardiac chamber ballooning
Synonyms:
Definition: The morphogenic growth in which the chambers of the heart expand in size, contributing to their shaping.
Ontology: GO: Biological Process [GO:0003242]    QuickGO    AmiGO