The more superficial cells of the epidermis become less viable and ultimately die. What two factors account for this natural demise of the epidermal cells?
1 Answer
The primary factor in the demise of the cells of the outer epidermal layer, known as the cornified layer, is the loss of water in the cells in the layer of dying cells.
The second factor is the infusion of keratin, a dense protein that hardens the skin cells to aid in producing a barrier against the outside world.
Explanation:
The primary factor in the demise of the cells of the outer epidermal layer, known as the cornified layer, is the loss of water in the cells in the layer of dying cells.
The second factor is the infusion of keratin, a dense protein that hardens the skin cells to aid in producing a barrier against the outside world.
New water rich cells are constantly produced in the germinative at the base of the epidermis. These columnar cells produced by mitosis as a means of growth, repair or replacement of the epidermal layers above.
These cells are pushed upwards into the layer of dying cells where cells lose 90% of their water content and flatten out. The proteins keratin and melanin are infused into the cells in this layer. Keratin hardens the cells to create in impenetrable exterior boundary. Melanin produced by specialized cells called melanocytes protect the skin from ultra violet light, giving the skin its coloration.
These cells are pushed upwards into the cornified layer of the epidermis. These flat squamous cells form the outer boundary of the skin. These are dead cells that constantly peel away as we wash, scratch, put on and take off clothes, get in and out of bed, etc....
Image from SMARTNotebook lecture from @smarterteacher
