mucous membrane /myo̅o̅″kəs/ [L, mucus + membrana, thin skin] , any one of four major kinds of thin sheets of tissue that cover or line various parts of the body. Mucous membrane lines cavities or canals of the body that open to the outside, such as the linings of the mouth, the digestive tube, the respiratory passages, and the genitourinary tract. It consists of a surface layer of epithelial tissue covering a deeper layer of connective tissue and protects the underlying structure, secretes mucus, and absorbs water, salts, and other solutes. Also called mucosa. Compare serous membrane, skin, synovial membrane.
