Mucosa in the respiratory system is composed of which type of tissue?

• A. Smooth muscle
• B. Pseudostratified ciliated columnar epithelium
• C. Stratified squamous epithelium
• D. Simple cuboidal epithelium

Answer: (B)

The mucosa in the respiratory system is primarily composed of pseudostratified ciliated columnar epithelium. This type of epithelial tissue is specifically adapted for the respiratory tract, where it plays a crucial role in trapping and expelling foreign particles, such as dust and pathogens, from the airways. The cilia on the surface of these epithelial cells beat in a coordinated manner to move mucus, which contains trapped particles, upward toward the throat, where it can be swallowed or expelled.

Additionally, the pseudostratified nature of this epithelium refers to the appearance of multiple layers, although all cells are attached to the basement membrane, giving the illusion of stratification. This structural feature allows for an effective barrier and efficient function in protecting the lungs from contaminants.

Other types of epithelial tissue mentioned do not fulfill the specific requirements or functions of the respiratory mucosa. For example, smooth muscle is responsible for contraction and movement but does not form the lining of the airways. Stratified squamous epithelium is typically found in areas subjected to abrasion, such as the skin and esophagus, not in the respiratory tract. Simple cuboidal epithelium is more common in glands and certain ducts rather than in the respiratory system