Serous Membrane

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Related to Serous Membrane: synovial membrane, cutaneous membrane

serous membrane

[′sir·əs ′mem‚brān]
A delicate membrane covered with flat, mesothelial cells lining closed cavities of the body.

Serous Membrane


(also tunica serosa), a connective-tissue membrane covered with an epithelial layer; it is approximately 1 mm thick and lines the body cavities of man and animals. Depending on its location, a serous membrane is called peritoneum, pleura, pericardium, or epicardium.

A serous membrane develops from a mesodermal derivative, or splanchnotome, which borders the secondary cavity of the body, or the coelom. The serous membrane produces and absorbs serous fluid and facilitates the movement and maintains the shape of the internal organs it surrounds, separates, or connects. It performs a protective function as a serohematolym-phatic barrier and is composed of several layers of dense and fibrous connective tissue. A serous membrane’s surface layer facing toward the body cavity is composed of a flat layer of epithelium called mesothelium.

The total extent of the body’s membranes is great. In man, the peritoneum covers approximately 20,400 cm2. A serous membrane is usually smooth, shining, transparent, and elastic; it becomes rough, dull, and thick during such inflammatory processes as peritonitis, pleurisy, and pericarditis, which cause functional disorders in the membrane. The growth of a serous membrane during pathological processes is accompanied by the formation of the commissures or by the adhesion and concrescence of the membrane’s layers.


References in periodicals archive ?
The peritoneum consists of serous membranes that line the peritoneal cavity through a network of mesothelial cells and collagen.
Cytological examination of cavity fluids may also reveal information about inflammatory conditions of the serous membranes, parasitic infestations, and infection with bacteria, fungi, or viruses.
The mesothelium forms the simple squamous epithelium that covers the surface of all true serous membranes.