Keratinization

The most important physiological function of the epidermis is to form a protective skin, the stratum corneum, to resist various stimuli from the outside. Epidermal cells will be funded according to the sequence of basal cells → acanth layer cells → granular layer cells → keratinocytes, and gradually move to the surface layer, eventually becoming keratinocytes. This process of epidermal cell differentiation is called "keratinization". Excessive keratinization of the epidermis can cause a series of skin diseases such as ichthyosis and palmoplantar keratosis, toadskin and menopausal keratosis.