Stratified squamous epithelium is a type of tissue composed of multiple layers of flat cells. This structure provides protection against physical and chemical damage, making it essential in areas of the body that experience friction, such as the skin, mouth, and esophagus. The outermost layer of cells can be keratinized, meaning they contain a protein called keratin, which helps to waterproof the skin and prevent water loss. This epithelium can be classified into two main types: keratinized and non-keratinized. Keratinized stratified squamous epithelium is found in the outer layer of the skin, while non-keratinized stratified squamous epithelium lines moist surfaces, such as the lining of the mouth and