(a)[2]
Explain why respiratory bronchioles do not contain goblet cells.
(b)
Fig. 4.1 shows a photomicrograph of a section through a bronchiole with alveoli around it.
(b(i))[3]
The epithelium of a bronchiole is structurally different from the epithelium of an alveolus. Describe the differences between bronchiolar epithelium and alveolar epithelium, other than any difference in goblet cell number.
(b(ii))[3]
Tissue X in Fig. 4.1 lies in the bronchiole wall. Name tissue X and describe the function of tissue X in the bronchiole.