What is the peritoneum?

• A. A single-layered membrane lining the abdomen
• B. The heart's protective sac
• C. Double-layered membrane surrounding abdominal organs
• D. A fibrous tissue in kidney

Answer: (C)

The peritoneum is a serous membrane that lines the abdominal cavity and covers its organs. It is arranged in two layers: the parietal peritoneum on the abdominal wall and the visceral peritoneum covering the internal organs. Between these layers is the peritoneal cavity, a potential space containing lubricating fluid that allows smooth movement of the organs during digestion and other activities. This double-layered arrangement and the presence of a lubricating cavity are what define the peritoneum.

This description matches a double-layered membrane surrounding abdominal organs, which is why it’s the correct choice. The heart’s protective sac is the pericardium, not the peritoneum, and the fibrous tissue around the kidney is not the peritoneum.