Serous membrane

Serous membranes have two layers. The parietal layers of the membranes line the walls of the body cavity (pariet- refers to a cavity wall). The visceral layer of the membrane covers the organs (the viscera). Between the parietal and visceral layers is a very thin, fluid-filled serous space, or cavity.[4]

Visceral and parietal layers

Each serous membrane is composed of a secretory epithelial layer and a connective tissue layer underneath.

• The epithelial layer, known as
  nucleated cells (simple squamous epithelium) which produce the lubricating serous fluid. This fluid has a consistency similar to thin mucus
  . These cells are bound tightly to the underlying connective tissue.
• The connective tissue layer provides the
  nerves
  for the overlying secretory cells, and also serves as the binding layer which allows the whole serous membrane to adhere to organs and other structures.

The

• A serous membrane lines the
  pericardial cavity of the heart, and reflects back to cover the heart, much like an under-inflated balloon would form two layers surrounding a fist. Called the pericardium, this serous membrane is a two-layered sac that surrounds the entire heart except where blood vessels emerge on the heart's superior side;^[4]
• The
  pleura
  is the serous membrane that surrounds the lungs in the pleural cavity;
• The peritoneum is the serous membrane that surrounds several organs in the abdominopelvic cavity.
• The tunica vaginalis is the serous membrane, which surrounds the male gonad, the testis.

The two layers of serous membranes are named parietal and visceral. Between the two layers is a thin fluid filled space.^[4] The fluid is produced by the serous membranes and stays between the two layers to reduce friction between the walls of the cavities and the internal organs when they move with respect to one another, such as when the lungs inflate or the heart beats. Such movement could otherwise lead to inflammation of the organs.^[4]

Development

All serous membranes found in the human body formed ultimately from the

As the embryo develops, the mesoderm starts to segment into three main regions: the paraxial mesoderm, the intermediate mesoderm and the lateral plate mesoderm.

The lateral plate mesoderm later splits in half to form two layers bounding a cavity known as the

• The splanchnopleure is associated with the underlying endoderm with which it is in contact, and later becomes the serous membrane in contact with visceral organs within the body.
• The somatopleure is associated with the overlying ectoderm and later becomes the serous membrane in contact with the body wall.

The intraembryonic coelom can now be seen as a cavity within the body which is covered with serous membrane derived from the splanchnopleure. This cavity is divided and demarcated by the folding and development of the embryo, ultimately forming the serous cavities which house many different organs within the thorax and abdomen.

Diseases

• 
  Layers of stomach wall
• 
  Section of duodenum of cat

See also

• Adventitia

References

This Wikipedia entry incorporates text from the freely licensed Connexions [1] edition of Anatomy & Physiology [2] text-book by OpenStax College