What is the difference between keratinized and non keratinized squamous epithelium?

The cells of the outer layers have their cytoplasm replaced with a hard waterproof protein called kera­tin. The process of replacement of cytoplasm is called keratinisation or karnification. The keratinised cells are dead cells and are referred to as horny layers eg. the epidermis of the skin in land vertebrates or terrestrial vertebrates.

Non Keratinized Stratified Squamous epithelium. This tissue lines the buccal cavity, pharynx and oesophagus . Here the cells are living even at the surface because cytoplasm is not replaced by keratin. This layer how­ever is not waterproof and affords some degree of protection.