Which lining forms the mucous barrier of the respiratory tract?

Which lining forms the mucous barrier of the respiratory tract?

• A. Serosa
• B. Adventitia
• C. Goblet cells
• D. Mucous membrane

Answer: (D)

Forming a protective, sticky barrier in the airways is the mucous membrane. This lining, also called the mucosa, consists of epithelium (often ciliated), with goblet cells that secrete mucus. The mucus coats the airway surface and, together with the beating cilia, creates the mucociliary escalator that traps inhaled particles and helps move them out of the respiratory tract. Goblet cells contribute to the barrier by supplying mucus, but they are part of the mucous membrane rather than the lining itself. Serosa and adventitia are different types of coverings outside the mucous lining, not the lining that forms the mucous barrier.

Forming a protective, sticky barrier in the airways is the mucous membrane. This lining, also called the mucosa, consists of epithelium (often ciliated), with goblet cells that secrete mucus. The mucus coats the airway surface and, together with the beating cilia, creates the mucociliary escalator that traps inhaled particles and helps move them out of the respiratory tract. Goblet cells contribute to the barrier by supplying mucus, but they are part of the mucous membrane rather than the lining itself. Serosa and adventitia are different types of coverings outside the mucous lining, not the lining that forms the mucous barrier.