Term: atrium epithelium
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: epithelium
Synonyms:
Definition: Portion of tissue, that consists of one or more layers of epithelial cells connected to each other by cell junctions and which is underlain by a basal lamina.
Ontology: Anatomy Ontology [ZFA:0001486]