The outer layer of human skin is called the epidermis. This layer is not just on the skin?s surface but also has many levels, each with their own function.
The deepest level of epidermis contains active, growing cells. New cells are then pushed up through the other levels of epidermis to the surface, dying along the route. Dead cells fill with keratin, a strong protein. These keratin-laden cells comprise the outer layer of the epidermis, providing the body with much-needed protection. Because the body continually sheds old cells, replacing them with new, humans have an entirely new skin surface every 20 to 30 days.
The inner layer of skin ? thick connective tissue ? is called the dermis. Contained within the dermis is the body?s network of nerves and receptors that produce a human?s sense of touch, pressure and pain.