In this chapter, all four patients experience difficulty breathing. Students will determine the lung capacity of each patient using a spirometer, which requires the patient to exhale deeply in order to determine if diseases such as asthma, pneumonia, and bronchitis are compromising the respiratory system. Students are asked to take a peek at class notes to refresh their memory of lung capacity. This Teacher Guide chapter highlights the Before the Lesson, During the Lesson, and After the Lesson instructions and recommends that the teacher read prior to starting the lesson. To learn more about the Student Edition chapter referenced here, check out “ Let’s Diagnose Them, Lab 5: Lung Capacity.”