1. Take a closer look at the main structures of the organ:
- you will see the lamina propria lined with pseudostratified ciliated columnar epithelium;
- in the pseudostratified ciliated columnar epithelium, identify the ciliated cells, goblet cells and intercalated cells;
- in the loose connective tissue of the lamina propria on the border with the submucosa, identify bundles of longitudinal elastic fibers (cut in cross section, so they appear as eosinophilic, glass-like dots);
- the layer under the mucosa is the submucosa where you will find sero-mucous glands. Excretory ducts from these glands pass through the lamina propria to the epithelium and tracheal lumen. The submucosa also contains many blood vessels;
- outside the connective tissue layers - the fibromusculocartilagineous layer (observe the rings of hyaline cartilage; rings of hyaline cartilage; these ‘rings’ are incomplete and C-shaped). Outermost is a layer of connective tissue, known as the adventitia.
2. Draw and sign:
- I – t. mucosa
(1 - pseudostratified ciliated columnar epithelium, 2 - loose connective tissue of the lamina propria, 3 - bundles of elastic fibers, 4 – excretory ducts of the glands);
- II - t. submucosa (5 – secretory partt of the mixed glands);
- III - fibromusculocartilagineous layer (6 – hyaline cartilage);
- IV - t. adventitia (7 – blood vessels; 8 - adipocytes).
3. Define and write significant features of the slide.