Which term describes the outer layer of a serous membrane lining a body cavity?

• A. Parietal
• B. Visceral
• C. Mucosa
• D. Serosa

Answer: (A)

Parietal describes the outer lining of a serous membrane that lines the walls of a body cavity. A serous membrane has two layers: the parietal layer attaches to the cavity wall, and the visceral layer covers the organ inside the cavity. The space between them contains serous fluid to reduce friction as organs move. The term serosa refers to the membrane itself as a whole, not specifically the outer lining, and mucosa describes membranes that line passages open to the outside, not closed body cavities.