Asthma Flashcards
What is asthma?
A chronic inflammatory disease of the conducting airways
What causes airflow restriction?
Bronchoconstriction (smooth muscle contracts, lumen diameter decreases)
Mucus hyper-secretion (blocks airways, airway mucus plugging)
Airway hyper-responsiveness (exaggerated airway narrowing in response to stimuli)
What cell types are involved?
Mast cells
T and B lymphocytes
Eosinophils
Epithelial cells
What are the 4 phases of the allergic response?
Sensitisation to allergen
Early phase response
Late phase response
Airway remodelling
What are some examples of allergens?
Dust mites (proteins in their faeces); animal dander/hair (protein in dead skin); proteins in pollen
What is a dendritic cell?
A type of antigen presenting cell (APC). Act as a messenger between innate and adaptive systems
What do APCs do?
Survey the environment for pathogens, extend processes into lumen
What are the four processes in the Sensitisation to Allergen stage?
Allergen uptake
Allergen processing
Antigen presentation
Antigen recognition
What cells play a critical role in the Re-exposure to Antigen stage?
Mast cells
Where are mast cells located in the body, and how does their number compare with asthmatics?
Located in airway walls. Increase in number in asthmatics
What happens when IgE binds to mast cells?
Mast cells degranulate
What are the 6 inflammatory mediators?
Histamine, IL-4, IL-5, IL-14, LTC4, PGD2
What inflammatory mediators are responsible for bronchoconstriction?
Histamine, LTC4, PGD4
What are IL-4 and IL-13 both responsible for?
IgE synthesis and secretion
What is IL-5 responsible for?
Eosinophil recruitment
