serous membrane

a MEMBRANE lining a large CAVITY in the body. The membranes are smooth and transparent and the surfaces are moistened by fluid derived from BLOOD or LYMPH serum (hence the name). Examples are the PERITONEUM and the PERICARDIUM . Each consists of two layers: the visceral, which surrounds the organs, and the parietal, which lines the cavity. The two portions are continuous and the surfaces are close together, separated by fluid that permits free movement of the organs.