What type of epithelium mostly lines the respiratory tract?

The respiratory tract is primarily lined by pseudostratified ciliated columnar epithelium, which is specialized for both protection and the movement of mucus. This type of epithelium appears to have multiple layers due to the varying heights of the cells, but each cell actually reaches the basement membrane, classifying it as a single layer. The cilia on the surface play a crucial role in trapping and moving particles, such as dust and pathogens, out of the respiratory passages, facilitating respiratory function and maintaining airway hygiene.

Additionally, the presence of goblet cells within this epithelial layer contributes to the secretion of mucus, which aids in trapping inhaled particles. This combination of cilia and mucus production is vital for efficient respiratory defense mechanisms. Understanding the structure of pseudostratified ciliated columnar epithelium highlights its importance in respiratory health, as it effectively cleans the air we breathe while also providing a protective barrier against pathogens and irritants.