Asthma Flashcards
What is the purpose of the respiratory system?
- Transfer O2 from the environment to RBC’s
- Transfer CO2 from the blood to the air
- Regulate acid-base balance
Describe the bronchial system:
Bronchioles divide 22 in total.
What are the characteristics asthma?
- variable air flow obstruction
- inflammation and remodelling
- hyperresponsive
- thickening of basement membrane (airway wall remodelling)
- inflammatory cell infiltrate permeates the sub mucus a generates the airway wall remodelling leading to airflow obstruction:
- reduced airflow on expiration
- reduced FEV1 to <80%.
- measured in spirometry
- Occlusion of the airway by airway mucus
How id asthma tested for?
Breath in salt water and cough out sputum
What occurs when allergic (allergic and non-allergic aviation pathway)?
- Eosinophilic inflammation induced by allergen species and non-allergen-specific pathways.
- Allergens picked up by dendritic cells, presented to naïve T cells in airway submucosa where they’re presented to a T cell and stimulates B-cells which provide IGE and call mast cells
- Mast Cells: can then create a production of mucus and draw eosinophils to the airway.
What is the role of IgE?
- Mast cells bind IgE
- IgE –> lowest serum concentration of all antibodies
- Dominantly tissue bound to F(CE)R1 on mast cells and basophils.
- F(CE)R1 receptor density strongly correlated with F2-4, IgE.
What are some asthma triggers?
- Air pollution
- Allergens
- Exercise
- Viral infections: responsible for 78% of asthma addmissions to hosptials in chidlren, 70% in adults (flu most common).
- Cigarettes
- asthma thunderstrom
Impact of pollen in causing asthma:
- contains male gametes and consists of showering plants
- plants use either the wind or animals (or both) to carry pollen between individuals
- a fine powdery substance produced by plants in their process of sexual reproduction.
- contains the gametes, pollen itself isn’t the gametes.
- grasses are wind pollinated
How do you count pollen?
- Machine collects pollen in through a vacuum at the same rate humans breath
- sticky slide collects the pollen grains.
- pollen grains are stained and counted.
What is thunderstorm asthma?
- 10th wettest spring on record.
- Causes:
- high levels of grass pollen
- dusty thunderstorms - causes fragmentation of pollen molecules as they can be respired.
Do mast cells and histamine die?
No, release over a peroid of time, resynthesise their mediators and re-package them into granules.
What is the role of IgE in the response to allergens?
- IgE can bind to the high-affinity F(CE)R1 receptor on mast cells waiting to encounter allergens sensitive to them.
Why do we have mast cells?
Protective role:
1. certain bacteria
2. certain viruses
3. certain parasitic worms (IgE also important)
4. some cancers
5. Last defence/immune (surveillance)
6. Certain venoms.
How did allergies arise?
Hygiene hypothesis:
- cleanily westernised lifestyle caused a decreased encounter w/ organisms (e.g. farm animals) that woudl have pushed immune systems certain ways.
- immune system isn’t redirected producing IgE instead.
Old friends/microbiota hypothesis:
- used to having organisms around us
- entire microbiome considered in the environment
Epithelial barrier hypothesis:
- exposure to chemicals leads to damage of the epithelium in turn triggering T(c) type immunity.
What are some features of useful medicine?
- effective: have therapeutic action for which they are indicated.
- convenient: once a day tablet
- well-tolerant: slow side effects
- safe
- not too expensive
