Serous membrane

Serous membrane or serosa is a smooth tissue membrane consisting of two layers of mesothelium, which secrete serous fluid. The inner layer that covers organs (viscera) in body cavities is called the visceral membrane. A second layer of epithelial cells of the serosa, called the parietal layer, lines the body wall.

Structure

Serous membranes line and enclose several body cavities, known as serous cavities, where they secrete a lubricating fluid which reduces friction from muscle movement. Serosae have special names given to them, and are classified into:

• Pleura: The pleural serosa, in the thoracic cavity, is divided into the parietal pleura (lining the inside of the body wall) and the visceral pleura (covering the lungs).
• Peritoneum: The peritoneal serosa, in the abdominal cavity, is divided into the parietal peritoneum (lining the inside of the body wall) and the visceral peritoneum (covering the abdominal organs).
• Pericardium: The pericardial serosa, in the pericardial cavity, is divided into the parietal pericardium (lining the inside of the body wall) and the visceral pericardium (covering the heart).

Function

The serous membranes produce serous fluid, a thin, watery form of lubrication that allows organs to slide against each other without causing damage during muscle contractions.

Clinical significance

Inflammation of the serous membranes often results in serous fluid build-up in the serous cavities, a condition known as an effusion. This can occur in various diseases, such as pleurisy and peritonitis.

See also

• Mesothelium
• Endothelium
• Parietal layer
• Visceral layer

Serous_membrane

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  Serous Membrane
• Serous Organ Invagination
  Serous Organ Invagination
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  Illustration of Stomach Layers
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  Gray's Anatomy Plate 1058