Mucous membrane

Mucous membrane
Histological section taken from the gastric antrum, showing the mucosa of the stomach
Details
Precursor	ectoderm
Identifiers
Latin	tunica mucosa
MeSH	D009092
Dorlands /Elsevier	Mucous membrane
Anatomical terminology []

A mucous membrane or mucosa is a membrane that lines various cavities in the body and surrounds internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It is mostly of endodermal origin and is continuous with the skin at various body openings such as the eyes, ears, inside the nose, inside the mouth, lip, the urethral opening and the anus, frenulum of tongue, tongue. Some mucous membranes secrete mucus, a thick protective fluid. The function of the membrane is to stop pathogens and dirt from entering the body and to prevent bodily tissues from becoming dehydrated.

Developmentally, the majority of mucous membranes are of endodermal origin. Exceptions include the palate, cheeks, floor of the mouth, gums, lips and the portion of the anal canal below the pectinate line, which are all ectodermal in origin. They are composed of one or more layers of epithelial cells that secrete mucus, and an underlying lamina propria of loose connective tissue. The type of cells and type of mucus secreted vary from organ to organ and each can differ along a given tract.