Mucosa

Mucosa

The Mucosa, also known as the mucous membrane, is a type of tissue that lines various cavities in the body and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It is often associated with secretory glands that are either directly part of its structure, such as goblet cells, or that deliver their products into the mucosa, such as the exocrine glands.

Structure

The mucosa is a moist tissue layer that lines hollow organs and body cavities that are exposed to the external environment. In the digestive system, for example, the mucosa layer makes up the innermost layer of the gastrointestinal tract. The mucosa layer is vital in the process of absorption and secretion.

Epithelium

The epithelium of the mucosa is of various types according to the organ it covers, it may be stratified squamous epithelium (non-keratinized), as in the esophagus and vagina, or specialized columnar as in the bronchi of the lungs.

Lamina propria

The lamina propria is a layer of connective tissue that supports the epithelium, and also binds it to the muscular layer, the muscularis mucosae.

Muscularis mucosae

The muscularis mucosae is a thin layer of smooth muscle cells, which serves to throw the mucous membrane of the stomach and small intestine into small folds, increasing the surface area for absorption and secretion.

Function

The primary functions of the mucosa are secretion, absorption, and protection. The mucosa must also deal with the immune response to potential pathogens.

Clinical significance

Diseases of the mucous membranes can cause a variety of symptoms, such as dysphagia (difficulty swallowing), dysuria (painful urination), and dyspnea (shortness of breath).

See also

• Mucous gland
• Mucin
• Mucosal immune system
• Mucosal vaccine
• Mucosal atomization device