Term: brain lumen formation, open tracheal system
Name: brain
Synonyms: brain structure
Definition: Cavitated compound organ which is comprised of gray and white matter and surrounds the cerebral ventricular system.
Ontology: Anatomy Ontology [ZFA:0000008]

Name: lumen formation, open tracheal system
Synonyms: tracheal lumen formation
Definition: Creation of the central hole of a tube in an open tracheal system through which gases flow.
Ontology: GO: Biological Process [GO:0035149]    QuickGO    AmiGO