A lining epithelium, including glandular tissue, an underlying layer of loose connective tissue called the lamina propria, which provides vascular support for the epithelium, and often contains mucosal glands. Products of digestion pass into these capillaries. Lymphoid follicles, and plasma cells are also often found here. Finally, a thin double layer of smooth muscle is often present - the muscularis mucosa for local movement of the mucosa.