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The Effect of Smoking on Cells of the Respiratory Tract

The more than 4,000 chemicals found in tobacco smoke damage the cells of the nose, throat and lungs. Of these, 250 are known to cause cancer or are poisonous or radioactive. The combined effects of the chemicals and the body's defenses eventually make it harder to breathe, encourage infections and cause cancer or emphysema.

  1. Irritation

    • The nose, throat and airways of the lungs are lined with cells that trap particles and organisms. Some make mucus. Others, the cilia, have tiny hairs to move mucus and debris to be swallowed and destroyed by digestion.

      Introduced to smoke, the lining of the respiratory tract swells. The mucus gets thicker. A smoker may develop a cough to clear his throat.

    Tar

    • In a year, the lungs of a pack-a-day smoker are coated by up to a cup of tar. The tar paralyzes the cilia. The mucus becomes thicker.

    Weakened Defenses

    • Smoking also makes it harder for the white blood cells--scavenger cells--to trap invading organisms. The body can no longer fight infections as well as it once could. A smoker is more likely to get chronic bronchitis, pneumonia and other infections.

      Puff by puff, cancer-causing chemicals flow over the cells of the respiratory tract. In some cells, this causes changes--mutations--that cause the cells to divide wildly. They create cancer tumors.

    Ruptured Air Sacs

    • Deep inside the lungs are the air sacs. These tiny balloon-like structures surrounded by blood vessels are where the body picks up oxygen. Smoke contains carbon monoxide (the gas found in car exhaust). Red blood cells can grab carbon monoxide more easily than oxygen. The heart and lungs have to work harder to take in enough oxygen. The chemicals in smoke interfere with elastin, an enzyme that keeps the lung tissues flexible. The air sacs get stiff. They are easily torn, leaving fewer air sacs working hard to get oxygen. This is the start of emphysema.

    Quitting

    • No matter how long a person has smoked, quitting brings improvements fast. The longer a person goes without smoking the greater the improvement in his health.

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