Question

Identify and discuss three causative factors of both emphysema and chronic bronchitis.

Answer 1

The medical term “emphysema” means a respiratory tract abnormality characterized by the overstretching of alveoli. Emphysema results in decreased lung density because of over distention of the lung tissue by air. The most common risk factor of emphysema is, cigarette smoking.

The inflammation of bronchi is called, bronchitis. Chronic bronchitis is characterised by persistent inflammation of airways of lungs and increased secretion of mucous. It occurs due to the recurrent airway infections.

Both the emphysema and bronchitis are the COPD (chronic obstructive pulmonary diseases), which are irreversible conditions.

Causes of emphysema and chronic bronchitis:

1). Cigarette smoking:

Cigarette smoking causes direct irritating effect on the lungs. Due to the irritation by smoking, hyperplasia of the cells occur. Some of the effects of smoking on respiratory system are given below:

1. Nicotine causes constriction of the terminal bronchioles, which impair the pulmonary respiration
2. Cigarette smoke contains carbon monoxide, which binds to haemoglobin with high affinity and reduce the oxygen-binding capacity of haemoglobin
3. The smoke contains irritants, which enhance the mucosal secretion and constrict the airways, trigger an inflammatory reaction, called "bronchitis"
4. Continuous exposure to irritants reduces the elasticity of the airways and thus, reduces the respiratory capacity of the lungs. This condition lead to emphysema.

2). Exposure to toxic environmental chemicals: For example, exposure to pollutants and chemical fumes also destroy the respiratory mucosal lining and cause persistent irritation. It trigger the inflammatory response (bronchitis), and emphysema

3). Genetics: Certain genetic defects or family history of respiratory diseases also increase the risk of bronchitis and emphysema.

4). Recurrent airway infections causing chronic bronchitis: It occurs due to reduced immune response, nutritional deficiency, or lack of hygiene conditions.

The lining of air sacs is destroyed in emphysema after chronic smoking, exposure to the toxic environmental chemicals, or due to genetic defects, which creates air pockets in lungs. So, inhalation of the air causes it to get trapped in these air pockets and is difficult to exhale.

About 80% COPD cases are due to smoking. COPD is associated with enhanced chronic inflammatory response of lungs and airways to the noxious particles which are primarily caused by cigarette smoking.