BIOLOGY Volume 1 - A Guide to General Biology - 2004

9. UTILIZATION OF ENERGY

9.7. Diseases of the Respiratory System

9.7.4. Bronchitis

Bronchitis is an inflammatory disease of the Bronchi primarily affecting the mucous membrane. It occurs in both acute and chronic forms. Chronic bronchitis develops gradually and persists over a long period. Acute bronchitis has a sudden onset and runs a relatively short course, usually resolving within a few days. Acute bronchitis frequently accompanies common colds.

Chronic bronchitis presents a much more serious problem and is a widespread condition. The United Kingdom has the highest mortality rate from chronic bronchitis in the world (1 in 2,000 people per year, totaling around 30,000 deaths annually). There are approximately 1 million sufferers, with men outnumbering women three to one. The mortality rate among smokers is six times higher. Bronchitis is frequently accompanied by pulmonary emphysema, particularly in later stages. Like emphysema, it is largely linked to smoking and, to a lesser extent, air pollution. It is also characterized by a feeling of shortness of breath due to impaired gas exchange. The tars present in cigarette smoke are primarily responsible for the inflammation of the bronchial mucosa. One of the symptoms of bronchitis is excessive mucus production by epithelial goblet Cells in response to irritation. In smokers, the cilia responsible for sweeping mucus along the bronchi become paralyzed or destroyed. Consequently, the main symptom is a persistent cough that expels excess sputum, which eventually becomes thick and yellowish-green. As the disease progresses, the cough worsens and breathing becomes increasingly difficult. The more respiratory function is impaired, the greater the likelihood of secondary conditions developing on this Background, particularly Pneumonia.