Detail of the zone in contact with the lumen observed with the objective of 100x. We can observe the stratified squamous epithelium showing the superficial cells during moulting. We can also notice the difference between these squamous epithelial cells and the deep ones, containing a large and pigmented nucleus. In the submucous are visible abundant blue-stained collagen fibers. The rest is occupied by numerous nuclei (yellow), mainly of fibrocytes, and some blood vessels