Mucous membrane

A mucous membrane or mucosa (plural, mucosae or mucosas; Latin tunica mucosa) is a biological membrane that lines various cavities in the body and surrounds internal organs. It is of endodermal origin and consists of a layer (or layers) of epithelial cells overlying a layer of loose connective tissue. It is continuous with the skin at various body openings such as the eyes, ears, nose and mouth, the urethral opening and the anus. 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.

Structure and function

The mucous membrane is a lining of mostly endodermal origin. It consists of an epithelium (a layer, or layers of epithelial cells) and an underlying lamina propria of loose connective tissue. Mucosae line various cavities of the body that are either externally exposed to the environment or are internal organs, and the mucous membranes ensure that the underlying lamina propria of connective tissue remains moist. They are at several places contiguous with skin: at the nostrils, the lips of the mouth, the eyelids, the ears, the trachea, the stomach, the genital area, and the anus.