Mucous Membrane

Mucous membranes line the walls of internal hollow organs and surfaces of (a few) external body parts (e.g. conjunctiva of the eye and the outer layer of the glans) and produce a mucus that keeps their surface moist. Mucous membranes have no epidermis and no hair.

https://de.wikipedia.org/wiki/Schleimhaut _{(Wikipedia CC-by-sa-3.0)}