Final answer:
The parietal peritoneum is a serous membrane that lines the abdominal wall and is part of the peritoneum which also includes the visceral peritoneum that covers the abdominal organs. The peritoneal cavity lies between these two layers, containing lubricating fluid.
Step-by-step explanation:
The parietal peritoneum is the portion of the peritoneum that lines the abdominal wall. This serous membrane is one of two main regions of the peritoneum, with the other being the visceral peritoneum, which envelopes the abdominal organs. The parietal peritoneum is not to be confused with the visceral peritoneum, which directly covers the organs themselves. The peritoneal cavity is a fluid-filled space that exists between the parietal and visceral layers, and it contains a small amount of fluid to reduce friction between the two surfaces. It's important to note that not all organs are enveloped by the peritoneum; some, such as the duodenum, pancreas, and portions of the large intestine, are located behind the peritoneum in a position referred to as retroperitoneal.