Final answer:
The dead cells that contain keratin and are often peeled or scraped off are known as keratinocytes, found in the stratum corneum of the skin. These cells create a protective barrier and are an essential part of the hair and nails. They are continuously replaced by new cells from the lower layers of the epidermis.
Step-by-step explanation:
The dead cells described are keratinocytes found in the stratum corneum of the epidermis. These cells are rich in keratin, which confers hardness and water-resistance to the skin, hair, and nails.
Keratinocytes originate from the deepest layer of the epidermis, the stratum basale, and gradually move up through the epidermal layers, accumulating keratin as they go. Upon reaching the stratum corneum, they are no longer alive and are compacted to form a protective barrier. This layer is constantly shedding off the body, a process that is balanced by the production of new cells beneath it. This turnover is essential for the maintenance of a healthy epidermis and the overall protection it provides to the body.
An interesting feature of these cells is their role in the creation of hair shafts, as well as being part of the composition of nails. Both hair and nails are made of dead keratinized cells, which have hardened and dried out but still serve a protective and aesthetic function in the body.