definition of asthma
Asthma (or Asthma bronchiale) is a disease that hurts the airways inside the lungs. It causes the tissue inside the airways to swell. Asthma also causes the bands of muscle around the airways to become narrow. This makes it hard for enough air to pass through and for the person to breathe normally. Asthma also causes mucus-making cells inside the airways to make more mucous than normal.