| 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 muscle cell | 
|---|---|
| Synonyms: | cardiac muscle cells, cardiac myocyte, cardiomyocyte | 
| Definition: | |
| Ontology: | Anatomy Ontology [ZFA:0009316] |