Final answer:
Keratin is a protective protein primarily located in the epidermis, not in the dermal layer of the skin. Keratinocytes in the stratum corneum are dead and regularly replaced, which prevents permanent damage to the skin when surface layers are rubbed off.
Step-by-step explanation:
The statement that keratin is a protective protein found in the dermal layer of the skin is False. Keratin is, in fact, a protective protein, but it is predominantly located in the epidermis, which is the outermost layer of the skin. Keratinocytes are the type of cells found in the epidermis that produce keratin. This protein helps to make our hair, skin, and nails tough and water-resistant. The dermis, which is beneath the epidermis, consists mainly of connective tissues that provide strength and elasticity and contains blood vessels, sensory receptors, hair follicles, and glands.
It is also important to note that the cells in the stratum corneum of the epidermis, which is the outermost layer, do not have a nucleus or organelles. They are filled with keratin and are no longer living. These cells are continuously sloughed away and replaced by new keratinocytes coming from the deeper layers of the epidermis.
When we rub off some of the surface layers of our skin using a rough washcloth, we are typically removing cells from the stratum corneum. Our skin is not permanently damaged because these cells are dead and are designed to be shed. New layers of keratinocytes that are rising to the surface replace the old, dead cells, thereby maintaining the integrity of the skin barrier.