HA14 shows a second example of a stratified squamous mucosal epithelium. The structure is the same as that in HA13, but the number of cell layers is smaller because this tissue is from an area of the body that undergoes less mechanical stress. Why is this stratified squamous mucosal epithelium? If this epithelium is injured/damaged, what cell layer regenerates the epithelium? An increase in stress on epithelia leads to thickening of a stratified epithelium. Prolonged stress on a simple or pseudostratified epithelium may lead to metaplasia, in which, for example, a pseudostratified epithelium with cilia changes to a stratified, squamous, mucosal epithelium.