The fauces are regarded as the two pillars of mucous membrane. One being anterior, known as the palatoglossal arch and the second is posterior, the palatopharyngeal arch. Between these two arches is the palatine tonsil. The mucous membranes (or mucosae; singular: mucosa) are linings of ectodermic origin, covered in epithelium, and are involved in absorption and secretion. ... Most commonly, the term tonsils refers to the palatine tonsils that can be seen in the back of the throat. ...