Final answer:
The parietal peritoneum is a serous membrane that lines the abdominal wall within the abdominopelvic cavity. It is distinct from the visceral peritoneum, which envelops the abdominal organs. The space between these layers, the peritoneal cavity, is filled with fluid to reduce friction.
Step-by-step explanation:
The parietal peritoneum is an integral part of the abdominal cavity's lining. This serous membrane is one of two primary layers of the peritoneum; the other being the visceral peritoneum. The parietal peritoneum specifically lines the inner surface of the abdominal wall, fundamentally serving as a protective layer. In contrast, the visceral peritoneum envelops the abdominal organs themselves, covering them like a form-fitting fabric. Between these two layers is a fluid-filled space known as the peritoneal cavity, which contains a lubricating fluid that reduces friction between abdominal organs during movement.
Much like other serous membranes in the body, the parietal peritoneum comprises squamous epithelial tissue along with an underlying layer of connective tissue. Its role includes not only protection and structural support but also the formation of the part of the cavity wall. It is crucial to note that certain organs, such as the duodenum and pancreas, are retroperitoneal, meaning they sit behind the peritoneum and are only partially covered by the visceral peritoneum.