La série sur la maladie se poursuit avec l’asthme (asthma). Vous trouverez
sur Wikipedia en anglais simplifié un article très complet, avec
des schémas et vous pourrez même écouter la respiration d’un asthmatique (wheezing) au stéthoscope.
Ici, je vous propose quatre schémas ou infographies. (Les
termes marqués comme des hyperliens sont expliqués en infobulles : placez
le curseur dessus pendant une à deux secondes) :
A. Pourquoi
l’asthme rend-il la respiration difficile ?
Air enters the respiratory
system from the nose and mouth, and travels through the bronchial tubes.
In an asthmatic person, the muscles of the bronchial tubes tighten and thicken, and the air
passages become inflamed and mucus-filled, making it difficult for air to move.
In a non-asthmatic person, the muscles around the bronchial tubes are relaxed
and the tissue thin, allowing for easy airflow.
B. Les
déclencheurs de l’asthme.
C. Le
déclenchement d’une crise d’asthme (anglais UK).
Asthma triggers are factors
that bring on the
symptoms or an attack by irritating the airways or worsening
the inflammation in the airways. These triggers can provoke attacks in
individuals who already have a tendency to asthma:
- Infections, usually by a virus (colds, flu)
- Allergens, most commonly house dust mites, pets or pollen grains
- Certain medications (aspirin)
- Smoking, irritants such as air pollution, sulphur dioxide and diesel fumes
- Strong smells, perfumes
- Changes in the weather, high humidity
- Emotions like anger, fear or excitement as well
as food additives such as tartazine (an artificial food colouring agent) can
also kickstart
an attack.
D. Les crises
d’asthme.
Attacks usually start as
an allergic reaction to pollen, smog, or another substance mistaken for a
threat by the body’s defense system.
How the lungs work:
- Fresh oxygen inhaled
- Travels through bronchial tubes
- Oxygen enters blood through thin alveoli walls
- Carbon dioxide passes from blood into alveoli and exhaled from
body.
Asthma attacks:
What can keep air from entering / leaving the lungs:
- Muscles surrounding airways tighten to constrict them
- Inflammation of lining shrinks passageway
- Excess mucus blocks airway