BIOM30001 Lecture Notes - Lecture 18: Atopy, Mast Cell, Allergen
Document Summary
Asthma and chronic obstructive pulmonary disease (copd) are obstructive lung diseases. Frequently involves chronic inflammation, associated with airway hyper-responsiveness. Symptoms: recurrent episodes of wheezing, breathlessness, chest tightness, and coughing. Acute response: allergen or noxious stimulus triggers asthmatic response. Mediated mostly through mast cells and other inflammatory cell types. Happens with every asthmatic exacerbation (i. e. every time a wheeze develops) Chronic response due to uncontrolled airway inflammation: microscopically recognisable changes in airway walls that convert airflow obstruction from brief/transient/recurrent episodes to a persistent state. Normal: ciliated epithelium at top, submucosal tissue, airway smooth muscle not visible. Chronic asthma (after months-years): collagen deposition, significant increase in smooth muscle volume in airways. Acute inflammation: e. g. hayfever season, cat allergy - smooth muscle constriction, wheeze. If stimulus is not controlled/avoided chronic inflammation: chronically hypersensitive. Nonspecific hyper-reactivity: develop symptoms not only to specific allergen, but to any mildly noxious stimuli (airway pollution, dry/cold air, cigarette smoke)
