The effects of tobacco smoke on the respiratory system include: irritation of the trachea (windpipe) and larynx (voice box) reduced lung function and breathlessness due to swelling and narrowing of the lung airways and excess mucus in the lung passages.
Throat and bronchial irritation occur from inhaling first- or secondhand cigarette smoke. Over time, smokers bronchi and lungs become scarred. Health problems such as chronic bronchitis and emphysema can set in, severely restricting respiration. These breathing obstructions prevent adequate oxygen from entering the bloodstream to the heart. Atherosclerosis due to smoking can also narrow the pulmonary blood vessels that carry oxygenated blood to the heart. This further reduces the amount of oxygen being pumped throughout the body.