Tubular organs have distinct tissue layers in the wall.
Starting from the lumen, the inner three layers form the tunica mucosa . The innermost layer is the lamina epithelialis , a layer of epithelium. Next is the lamina propria , a layer of connective tissue. In some organs, a layer of smooth muscle is present as the lamina muscularis . Below the mucosa is the tunica submucosa which is predominately connective tissue.