| Anatomy | Chronology of embryological development.Respiratory epithelium extends from the nasal fossa throughout the nasopharynx, larynx, trachea, bronchi and bronchioles |
| Physiology | Nasal and bronchial hyperresponsiveness to environmental and chemical stimuliNasobronchial reflex from environmental stimuli |
| Immunopathology | Immediate hypersensitivity and allergic responses and persistent allergic inflammation, characterised by eosinophilia occuring in upper and lower airwaysThere is a systemic immune response to airborne allergens |