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Chronic obstructive pulmonary disease

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of COPD -- emphysema and/or chronic bronchitis.


Alternative Names

COPD; Alpha-1 antitrypsin deficiency; Bronchitis - chronic; Chronic bronchitis; Emphysema


Introduction

Chronic obstructive lung disease (COLD), also known as chronic obstructive pulmonary disease (COPD), is characterized by a limitation of the airflow in the lung, which develops over time and is not totally reversible.

COLD is associated with a set of breathing-related symptoms:

The ability to exhale (breath out) gets worse over time.

Normal lungs and alveoli
The lungs are located in the chest cavity and are responsible for respiration. The alveoli are small sacs where oxygen is exchanged in the lungs.

The two major diseases in this category are emphysema and chronic bronchitis, both covered in this report. Asthmatic bronchitis , the other major COLD, is a condition that develops when a person with asthma is exposed to irritants, such as smoking, and develops a chronic cough. [For more information, see In-Depth Report #04, Asthma in adults .]

Because smoking is overwhelmingly the cause of both emphysema and chronic bronchitis, they often develop together and frequently require similar treatments and approaches. As chronic bronchitis often coincides with emphysema, it is frequently difficult for a physician to distinguish between the two.

Emphysema

Emphysema is a disease marked by destruction in the alveoli , grapelike clusters of air sacs at the end of the smallest airways (the bronchioles) in the lung. It generally takes the following course:

Chronic Bronchitis

Chronic bronchitis is defined as coughing and overproduction of mucus for at least 3 months, during at least 2 consecutive years. In chronic bronchitis, the disease process is generally marked by the following characteristics:

The Lungs

The lungs are two spongy organs surrounded by a thin, moist membrane called the pleura. Each lung is composed of smooth, shiny lobes; the right lung has three lobes, and the left has two. About 90% of the lung is filled with air; only 10% is solid tissue.

When a person inhales, air travels through the following pathways into the lungs:

  • Air is carried from the trachea (the windpipe) into the lung through flexible airways called bronchi .
  • Like the branches of a tree, bronchi divide successively into over a million smaller airways called bronchioles .
  • The bronchioles lead to grape-like clusters of microscopic sacs called alveoli .
  • In each adult lung there are millions of these tiny alveoli. The thin membrane of the alveoli allows oxygen and carbon dioxide to pass to and from capillaries .
  • During deep inhalation, the elastic alveoli unfold and unwind to allow this passage to occur.

Capillaries, the smallest of our blood vessels, carry blood throughout the body. Red blood cells carry oxygen throughout the body, and return carbon dioxide to the lungs; white blood cells are the critical infection fighters in our body.


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