Q. 4 Cigarette smoking causes emphysema. Give reason.
Emphysemais a chronic disorder of respiratory system, where inflation or abnormal distension of alveolar wall occurs. Cigarette smoking and the inhalation of other smoke or toxic substances over a period of time causes the damaging of septa between the alveol,, and ofits elastic tissue is replaced by the connective tissue in lungs. Hence, the respiratory surface decreases, thus causing the emphysema. tt Causes shortness of breath, production of sputum, chronic bronchitis, etc.
