Gas Exchange In Humans
Overview
Every cell in your body is burning glucose right now, and to do it they all need a steady supply of oxygen and a way to get rid of carbon dioxide. Your lungs are the organ that makes this exchange happen, trading gases with the air millions of times a day without you ever thinking about it.
In this lesson you will see how the lungs are built for fast diffusion, trace the path air takes from your nose to the alveoli, find out exactly how breathed-in air differs from breathed-out air, and learn how your ribs and diaphragm pump air in and out. You will also discover the clever cleaning system that keeps dust and germs out of your lungs.
Objectives
- Describe the features of gas exchange surfaces in humans, limited to: large surface area, thin surface, good blood supply and good ventilation with air
- Identify in diagrams and images the following parts of the breathing system: lungs, diaphragm, ribs, intercostal muscles, larynx, trachea, bronchi, bronchioles, alveoli and associated capillaries
- Investigate the differences in composition between inspired and expired air using limewater as a test for carbon dioxide
- Describe the differences in composition between inspired and expired air, limited to: oxygen, carbon dioxide and water vapour
- Investigate and describe the effects of physical activity on the rate and depth of breathing
- [Supplement] Identify in diagrams and images the internal and external intercostal muscles
- [Supplement] State the function of cartilage in the trachea
- [Supplement] Explain the role of the ribs, the internal and external intercostal muscles and the diaphragm in producing volume and pressure changes in the thorax leading to the ventilation of the lungs
- [Supplement] Explain the differences in composition between inspired and expired air
- [Supplement] Explain the link between physical activity and the rate and depth of breathing in terms of: an increased carbon dioxide concentration in the blood, which is detected by the brain, leading to an increased rate and greater depth of breathing
- [Supplement] Explain the role of goblet cells, mucus and ciliated cells in protecting the breathing system from pathogens and particles
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Lesson Evaluation
Congratulations on completing the lesson on Gas Exchange In Humans. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Which feature of the alveoli does NOT speed up gas exchange? A. a large surface area B. a thick muscular wall C. a thin wall D. a good blood supply Answer: B
- Compared with inspired air, expired air contains: A. more oxygen and less carbon dioxide B. less oxygen and more carbon dioxide C. more oxygen and more carbon dioxide D. less oxygen and less carbon dioxide Answer: B
- Which test shows that expired air contains more carbon dioxide? A. iodine turns blue-black B. Benedict's turns brick-red C. limewater turns milky D. biuret turns purple Answer: C
- During inspiration the diaphragm: A. relaxes and moves up B. contracts and moves down C. stays domed D. is not involved Answer: B
- The correct order of structures for air entering the lungs is: A. trachea, larynx, bronchus, alveolus B. larynx, trachea, bronchus, alveolus C. bronchus, trachea, larynx, alveolus D. alveolus, bronchus, trachea, larynx Answer: B
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