3.3.3 Chronic Obstructive Pulmonary Disease
Chronic obstructive pulmonary disease（COPD）is a chronic，progressive respiratory disease that blocks airflow，making it difficult to breathe.The three major disorders included in COPD are asthma，chronic bronchitis，and emphysema（Fig.3-6）.
Asthma produces spasms in the bronchial passages（bronchospasms）that may be sudden and violent（paroxysmal）and lead to dyspnea.Asthma is commonly caused by exposure to allergens or irritants.Other causes include stress，cold，and exercise.During recovery，coughing episodes produce large amounts of mucus（productive cough）.Treatment includes agents that loosen and break down mucus（mucolytics）and medications that expand the bronchi（bronchodilators）by relaxing their smooth muscles.
Fig.3-6 Chronic Obstructive Pulmonary Disease
Chronic bronchitis is an inflammation of the bronchi caused mainly by smoking and air pollution.However，other agents，such as viruses and bacteria may also cause the disorder.Bronchitis is characterized by swelling of the mucosa and a heavy，productive cough，commonly accompanied by chest pain.Patients usually seek medical help when they suffer from exercise intolerance，wheezing，and shortness of breath.Bronchodilators and medications that aid in the removal of mucus（expectorants）help to widen air passages.Steroids may be prescribed if the disease progresses or becomes chronic.
Emphysema is characterized by decreased elasticity of the alveoli.The alveoli expand but are unable to contract to their original size.The air that remains trapped in the chest results in a characteristic“barrel-chested”appearance.Most emphysema sufferers find it easier to breathe when sitting upright or standing erect（orthopnea）.Treatment for emphysema is similar to that of chronic bronchitis.
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Task 5 Fill in the blanks with proper words.
1.Asthma，chronic bronchitis，and_________are the major subtypes included in COPD.(https://www.daowen.com)
2.Spasms in the bronchial passages are referred to as________.
3.The sudden and violent attack or recurrence of a disease can be described as________.
4.________indicates coughing episodes producing large amounts of mucus.
5.Agents that loosen and break down mucus are called________.
6.________are prescribed to make breathing easier by relaxing the muscles in the lungs and widening the airways.
7.A（n）________is a type of cough medicine that people can use when they have a cough that produces mucus.
8.________is characterized by over-inflation and decreased elasticity of the alveoli.
9.The characteristic________appearance in patients with emphysema is caused by air that remains trapped in the chest.
10.________is a form of dyspnea in which a person finds it easier to breathe when sitting upright or standing erect.