What you’ll learn11 learning objectivesChoose one objective for a focused lesson, or study the complete topic.11.1.1Features of gas exchange surfaces• Describe the features of gas exchange surfaces in humans, limited to: large surface area, thin surface, good blood supply and good ventilation with airSyllabus objective11.1.2Following parts of the breathing• Identify in diagrams and images the following parts of the breathing system: lungs, diaphragm, ribs, intercostal muscles, larynx, trachea, bronchi, bronchioles, alveoli and associated capillariesSyllabus objective11.1.3Differences in composition between• Investigate the differences in composition between inspired and expired air using limewater as a test for carbon dioxideSyllabus objective11.1.4Differences in composition between• Describe the differences in composition between inspired and expired air, limited to: oxygen, carbon dioxide and water vapourSyllabus objective11.1.5Effects of physical activity on• Investigate and describe the effects of physical activity on the rate and depth of breathingSyllabus objective11.1.6Internal and external intercostal• Identify in diagrams and images the internal and external intercostal musclesSyllabus objective11.1.7Function of cartilage in the trachea• State the function of cartilage in the tracheaSyllabus objective11.1.8Ventilation mechanics• 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 lungsSyllabus objective11.1.9Differences in composition between• Explain the differences in composition between inspired and expired airSyllabus objective11.1.10Link between physical activity• 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 breathingSyllabus objective11.1.11Role of goblet cells, mucus• Explain the role of goblet cells, mucus and ciliated cells in protecting the breathing system from pathogens and particlesSyllabus objective