MEDICAL ANIMATION TRANSCRIPT: Smoking damages two main parts of your lungs, your airways, also called bronchial tubes, and small air sacs called alveoli. With each breath, air travels down your windpipe, called the trachea, and enters your lungs through your bronchial tubes. Air then moves into thousands of tiny alveoli, where oxygen from the air moves into your bloodstream and the waste product carbon dioxide moves out of your bloodstream. Tiny hair like projections called cilia line your bronchial tubes and sweep harmful substances out of your lungs. Cigarette smoke irritates the lining of your bronchial tubes, causing them to swell and make mucus. Cigarette smoke also slows the movement of your cilia, causing some of the smoke and mucus to stay in your lungs. While you're sleeping, some of the cilia recover and start pushing more pollutants and mucus out of your lungs. When you wake up, your body attempts to expel this material by coughing repeatedly, a condition known as smoker's cough. Overtime, chronic bronchitis develops as your cilia stop working, your airways become clogged with scars and mucus, and breathing becomes difficult. Your lungs are now more vulnerable to further disease. Cigarette smoke also damages your alveoli, making it harder for oxygen and carbon dioxide to exchange with your blood. Over time, so little oxygen can reach your blood that you may develop emphysema, a condition in which you must gasp for every breath and wear an oxygen tube under your nose in order to breathe. Chronic bronchitis and emphysema are collectively called chronic obstructive pulmonary disease, or COPD. COPD is a gradual loss of the ability to breathe for which there is no cure.