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Biology LibreTexts

16: Respiratory System

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  • This chapter describes the structure and function of the respiratory system, including how breathing occurs and what controls it, as well as how the process of gas exchange takes place in the lungs. The chapter also describes several disorders of the respiratory system and details the adverse health effects of smoking.

    • 16.1: Case Study: Respiratory System and Gas Exchange
      Three weeks ago, 20-year-old Erica came down with symptoms typical of the common cold. She had a runny nose, fatigue, and a mild cough. Her symptoms had been starting to improve, but recently her cough has been getting worse. She is coughing up a lot of thick mucus, her throat is sore from frequent coughing, and her chest feels very congested. According to her grandmother, Erica has a “chest cold.” Erica is a smoker and wonders if her habit is making her cough worse. She decides that it is time
    • 16.2: Structure and Function of the Respiratory System
      Why can you “see your breath” on a cold day? The air you exhale through your nose and mouth is warm like the inside of your body. Exhaled air also contains a lot of water vapor because it passes over moist surfaces from the lungs to the nose or mouth. The water vapor in your breath cools suddenly when it reaches the much colder outside air.
    • 16.3: Breathing
      The swimmer in this photo is doing the butterfly stroke. This swimming style requires the swimmer to carefully control his breathing so it is coordinated with his swimming movements. Breathing is the process of moving air into and out of the lungs, which are the organs in which gas exchange takes place between the atmosphere and the body. Breathing is also called ventilation, and it is one of two parts of the life-sustaining process of respiration, the other part being gas exchange.
    • 16.4: Gas Exchange
      Belly up to the bar and get your favorite — oxygen? That’s right; in some cities you can get a shot of pure oxygen, with or without your choice of added flavors. Bar patrons inhale oxygen through a plastic tube inserted into their nostrils, paying up to a dollar per minute to inhale the pure gas. Proponents of the practice claim that breathing in extra oxygen will remove toxins from the body, strengthen the immune system, enhance concentration and alertness, increase energy, and even cure cancer
    • 16.5: Disorders of the Respiratory System
      The scary beast in this photo is likely to be lurking in your own home, where it feeds on organic debris, including human skin. What is it? It’s the common dust mite, a close relative of spiders. The dust mite is so small that it is barely visible with the unaided eye, so it’s obviously shown above greatly enlarged.
    • 16.6: Smoking and Health
      This anti-smoking cartoon clearly makes the point that smoking causes death. The cartoon is not using hyperbole, because smoking actually is deadly.
    • 16.7: Case Study Bronchitis Conclusion and Chapter Summary
      The little girl shown above seems to be enjoying the air coming out of a humidifier. Inhaling the moist air from a humidifier or steamy shower can feel particularly good if you have a respiratory system infection, such as bronchitis. The moist air helps to loosen and thin mucus in the respiratory system, allowing you to breathe easier.