Lesson 7 of 8
Smoking and the lungs
Goal: Describe how smoking harms the gas exchange system.
Tobacco smoke carries harmful substances deep into the lungs. Three to know are tar, nicotine and carbon monoxide.
TarSticky. It coats the airways and alveoli and causes lung cancer.
NicotineAn addictive drug. It makes blood vessels narrower.
Carbon monoxideA poisonous gas. It takes the place of oxygen in red blood cells.
- Cilia are tiny hairs on the cells that line the airways. They sweep mucus, and the dirt and microbes stuck in it, up and out of the lungs.
- Smoke damages the cilia. Mucus builds up, which causes a smoker’s cough and more chest infections.
- Smoke also damages the walls of the alveoli. That leaves less surface area for gas exchange, so a smoker gets out of breath easily.
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Key words in this lesson
Gas exchange Taking in one gas and giving out another
Alveoli Tiny air sacs at the ends of the bronchioles
Tar The sticky substance in tobacco smoke that causes cancer
Nicotine The addictive drug in tobacco smoke
Carbon monoxide A poisonous gas that takes the place of oxygen in the blood