Title: Scheme of trachea
Scheme trachea, human adult. On top pseudostratified ciliated epithelium (1) with goblet cells followed by a condensed layer of elastic fibres (2) and the transition (*) to seromucous tracheal glands (3) close to the edge of the perichondrium (4) of hyaline cartilage (5).
Title: Longitudinal section of trachea
Stain Azan, human adult. On top: the epithelium (1) is pseudostratified with cilia and goblet cells on a distinct basement membrane (↓). There is almost no demarcation (at this magnification) between lamina propria and submucosa due to the dense blue (2) staining of elastic fibers reinforced by collagen fibers. Mixed seromucous tracheal glands (3) and fat cells (4, white) are localized in the submucosa, in between a red-stained blood vessel (*). The perichondrial edges of hyaline cartilage (6) are connected by a fibrous tissue (5, fibroelastic membrane).
Title: Section of trachea
Stain Azan, human adult. On top: the epithelium (1) is pseudostratified with cilia and goblet cells (white droplets) on a distinct basement membrane (↓, undulating thick deep-red line) followed by a small proper lamina (2). The submucosa (3) starts where the fibrous tissue (elastic fibers reinforced with collagen) becomes denser and deep blue (elastic fibers are almost masked due the staining). Mixed seromucous tracheal glands (4) (left side) and an excretory duct (5) draining into an epithelial invagination are localized within the submucosa. Below the perichondrium (*) of hyaline cartilage (6) which artifactually is separated from the submucosa.
Keywords/Mesh: respiratory tract, trachea, pseudostratified epithelium, , tracheal gland, excretory duct, hyaline cartilage, elastic fiber, fibroelastic membrane, perichondrium, histology, POJA collection