exists and is an alternate of . Making the world better, one answer at a time. 1) Position -- Mucous membranes line cavities that connect with the exterior, including the digestive, respiratory, reproductive, and urinary tracts. Serous membranes line the sealed, internal cavities of the body. the pericardium lines the pericardial cavity and covers the heart. 2) Function -- Mucous membranes protect the tracts from mechanical factor, chemical substances, and microorganism invasion. Serous fluid covers the surfaces to minimize friction between opposing surfaces. 3) Types -- Mucous membranes: simple epithelia, stratified squamous epithelium, the transitional epithelium. Serous membranes: there are parietal and visceral portions. Parietal lines the outer wall of the internal chamber.