title: Structure of the avian respiratory tract.
mesh_terms: D000400:Air Sacs / Q000033:anatomy & histology; D000818:Animals; D001717:Birds / Q000033:anatomy & histology*; D001980:Bronchi / Q000033:anatomy & histology / Q000098:blood supply; D008168:Lung / Q000033:anatomy & histology; D011652:Pulmonary Circulation; D012119:Respiration; D012137:Respiratory System / Q000033:anatomy & histology*