Asthma is a lung disease that inflames and narrows your airways.
Normally, as you inhale air moves freely through your trachea, or windpipe
通常情况下 人们吸气时 空气能在你的气管内自由流动
then through large tubes called bronchi
smaller tubes called bronchioles
and finally into tiny sacs called alveoli.
Small blood vessels, called capillaries, surround your alveoli.
Oxygen from the air you breathe passes into your capillaries
then carbon dioxide from your body passes out of your capillaries into your alveoli
so that your lungs can get rid of it when you exhale.
这样一来 呼气时 你的肺就可以将它排出
Your bronchioles expand when the air is warm, moist,
allergy causing substances called allergens.
When air is cold or dry,
or contains irritants or allergens,
your bronchioles contract.
If you have asthma,
your airways are frequently inflamed and swollen.
Certain substances can cause you are inflamed airways to overreact even more,
resulting in an asthma attack.
Triggers of asthma attacks are slightly different for everyone,
but usually include:
outdoor irritants and allergens,
such as pollen
indoor irritants and allergens,
such as mold
and cockroach droppings
such as fish
such as respiratory infections
shortness of breath, and tightness in your chest.
During an asthma attack (also known as a bronchospasm) the muscles around your airways tighten
and the airway wall becomes more swollen.
Your airways also produce thick mucus that narrows them even more
making it hard for you to breathe.
If you have asthma, your doctor may prescribe medications to reduce:
inflammation in your airways,
constriction of the muscles surrounding your airways,
or mucous secretion in your airways.
During an asthma attack
you may need to use a short-acting rescue medication
called a bronchodilator.
This medication causes your airway muscles to relax quickly
and provide symptom relief within minutes.
Since there is no cure for asthma,
the goal is to prevent you from having asthma attacks
by using long-acting, anti-inflammatory control medications.
If you take them every day, they will reduce the inflammation of your airways
making them less sensitive to triggers of asthma attacks.