Seroosikalvo

Seroosikalvo, or serous membrane, is a thin, slippery membrane that lines closed body cavities and covers the surfaces of many organs. It consists of two layers: a parietal layer lining the cavity wall and a visceral layer covering the organs; the space between them contains a small amount of serous fluid that lubricates moving surfaces.

Structure and cells: The membrane is primarily composed of mesothelium, a simple squamous epithelium, supported by connective tissue. Serous fluid is produced by the mesothelium and surrounding capillaries, creating a lubricating film.

Major serous membranes include the pleura around the lungs, the pericardium around the heart, and the peritoneum lining the abdominal cavity and covering organs. The tunica vaginalis around the testes is a serous membrane derived from the peritoneum.

Function: Serous membranes reduce friction as organs move and expand, help compartmentalize cavities, and act as a selective barrier. They also participate in fluid exchange between the cavity and the bloodstream.

Clinical relevance: Inflammation of serous membranes is called serositis and can affect any membrane, causing pleuritis, pericarditis, or peritonitis. Inflammation often leads to effusions and, in some cases, adhesions between surfaces.

Development and variation: Serous membranes arise from mesoderm during embryonic development and are found in many vertebrates. Abnormal growth of mesothelial tissue can lead to mesothelioma, a cancer linked to asbestos exposure in some cases.