The abdominal cavity is lined by peritoneum, which consists of an epithelial-like single layer of cells (the mesothelium) together with a supportive layer of connective tissue. Peritoneum is similar to the pleura and serous pericardium in the thorax.
The peritoneum reflects off the abdominal wall to become a component of the mesenteries that suspend the viscera.
Parietal peritoneum lines the abdominal wall.