Small bronchus in the lung (human, adult)

Stain: Azan. Pseudostratified epithelium (1) with in between light-stained goblet cells and a blue stained basement membrane (↓) with the proper lamina. The thin smooth muscle layer (2) is purple stained and accompanies the mucosal layer. At (3) a small hyaline cartilage and seromucous bronchial glands (4) with an excretory duct (6). A small site of carbon deposit (5) close to collapsed alveoli (#)