A view of the inside of the chest showing the lungs and pericardium.
A serous membrane istissue, also called a serosa, consisting of a layer of mesothelium attached to a surface by a thin layer of connective tissue. Serous membranes are covering membranes which line body cavities that do not open to the exterior. They are found around organs that move a lot, such as the heart and lungs.
The outer layer of a serous membrane is called the parietal layer and is always attached to the surrounding tissues. The inner layer is called the visceral layer and is firmly attached to the organ it covers.