Name the epithelium of the pleural membranes. Identify this space. Quiet exhalation is "passive". Describe why air leaves the lungs. Describe the trends with respect to tissue organization (esp. The amount of smooth muscle and cartilage, and the type of epithelium) as you move into smaller branches of the bronchial tree. Describe the chemical nature of surfactant. What is its function? Why are there fixed macrophages in alveoli? This application of Fick"s Law involves one cell membrane. Describe all of the layers involved in the diffusion of gasses across the respiratory membrane. Identify the type of muscle tissue in respiratory muscles. Explain why breathing is normally rhythmic and unconscious. Can these muscles be voluntarily controlled? Explain how this is possible. Describe the action of carbonic anhydrase in the respiratory centers. Apneustic Ctr. How do chemical changes influence activity in the respiratory centers of the Pons?