A mucosa, lining the lumen of any hollow organ opening to the exterior, is the most variable of the three membranes. It typically consists of an epithelium, a connective tissue lamina propria, and a muscularis mucosae of smooth muscle. A mucous membrane is so named because mucus-producing glands frequently secrete onto its surface, providing lubrication. 400x
The epithelium of a mucous membrane varies greatly depending on the location and function of the organ: simple columnar epithelium, simple cuboidal epithelium, pseudostratified epithelium, stratified squamous epithelium, or transitional epithelium.
The tubes extending through lamina propria are glands, secretory epithelium, whose secretions lubricate the surface of this organ.
Lamina propria >
The lamina propria of a mucosa is loose connective tissue. Because the ground substance of loose connective tissue is a gel, this layer provides good cushioning for its covering epithelium, padding for any glands present and diffusion of nutrients.
Muscularis mucosae >
The muscularis mucosae of a mucous membrane is smooth muscle. This layer may be incomplete or lacking in some organs.