has part develops from capable of material entity tracheocyte tracheole tracheolar cell Present at all developmental stages. tracheal end cell tracheoblast FBbt:00005048 Specialized cell of the tracheal system that forms the secondary and terminal branches (tracheoles) of the tracheal tree. Each forms a secondary branch of a primary trachea. This secondary branch itself branches into multiple tracheoles within fine cytoplasmic projections that invade (tracheate) target tissues. Tracheolar cells are the main site of respiratory gaseous exchange within the tracheal system. fly_anatomy.ontology terminal tracheal cell respiratory gaseous exchange by respiratory system