Mucous, slimy tissue or mucosal membrane. It covers the inside of the bowel, mouth, etc. Here is some mucosa meaning list.
It is a layer of endoderm origin that covers the inside of the mucous or slimy tissue lumen organs. The fluid secreted by the mucosa is called mucus (fluid).
Developmentally, the vast majority of mucous membranes are of endodermal origin. Exceptions; the palate, cheeks, mouth, gums, lips and the part below the pectin line of the anal canal are of ectoderm origin.
Mucosal membranes; It covers the inside of the digestive, respiratory and reproductive systems. In an adult person, the total surface area of the mucosa is about 400 square meters, while the surface area of the skin is about 2 square meters.